SYNTHESIS OF NEW 1223-TYPE LAYERED CUPRATE (Tl, V) (Sr, Ba)2Ca2Cu3O9 WITH TC(ρ=0) ABOVE 110 K

1993 ◽  
Vol 07 (11) ◽  
pp. 761-769 ◽  
Author(s):  
Z.Y. CHEN ◽  
Z.Z. SHENG ◽  
Y.F. LI ◽  
D.O. PEDERSON
Keyword(s):  
X Ray Diffraction ◽  
X Ray ◽  
Practical Applications ◽  
Layered Cuprates

A new series of 1223-type (Tl, V)-based layered cuprates (Tl, V)(Sr,Ba) 2 Ca 2 Cu 3 O 9 has been successfully synthesized and identified by powder X-ray diffraction. Partial substitutions of V for Tl and Ba for Sr promote the formation of (Tl, V)-based 1223-type compounds. Nominal samples ( Tl 1−x V x) ( Sr 2−y Ba y) Ca 2 Cu 3 O z with x=0.25–0.50 and y=0.25–1.50 are pure or nearly-pure 1223 phase and exhibit TC(ρ=0) in the range of 100–110 K. This new (Tl, V)-based high TC material may be of importance in practical applications.

Non-uniform distribution of dopant iron ions in TiO2 nanocrystals probed by X-ray diffraction, Raman scattering, photoluminescence and photocatalysis

2015 ◽  
Vol 3 (8) ◽  
pp. 1846-1853 ◽  
Author(s):  
S. Manu ◽  
M. Abdul Khadar
Keyword(s):  
Raman Scattering ◽  
Uniform Distribution ◽  
Semiconductor Nanocrystals ◽  
Iron Ions ◽  
X Ray Diffraction ◽  
Tio2 Nanocrystals ◽  
X Ray ◽  
Practical Applications ◽  
Mechanism Operative

The phenomenon of ‘self-purification’ is a real mechanism operative in nanocrystals and this should be taken into account while doping semiconductor nanocrystals with external impurities for practical applications.

Immobilization of hemoglobin on stable mesoporous multilamellar silica vesicles and their activity and stability

2005 ◽  
Vol 20 (10) ◽  
pp. 2682-2690 ◽  
Author(s):  
Yufang Zhu ◽  
Weihua Shen ◽  
Xiaoping Dong ◽  
Jianlin Shi
Keyword(s):  
Thermal Stability ◽  
Pore Size ◽  
X Ray Diffraction ◽  
X Ray ◽  
Practical Applications ◽  
Silica Material ◽  
Transmission Electron ◽  
Mesoporous Support ◽  
Adsorption Desorption ◽  
Thermal Stability Of

A stable mesoporous multilamellar silica vesicle (MSV) was developed with a gallery pore size of about 14.0 nm. A simulative enzyme, hemoglobin (Hb), was immobilized on this newly developed MSV and a conventional mesoporous silica material SBA-15. The structures and the immobilization of Hb on the mesoporous supports were characterized with x-ray diffraction, transmission electron microscopy, N2 adsorption-desorption isotherms, Fourier transform infrared, ultraviolet-visible spectroscopy, and so forth. MSV is a promising support for immobilizing Hb due to its large pore size and high Hb immobilization capacity (up to 522 mg/g) compared to SBA-15 (236 mg/g). Less than 5% Hb was leached from Hb/MSV at pH 6.0. The activity study indicated that the immobilized Hb retained most peroxidase activity compared to free Hb. Thermal stability of the immobilized Hb was improved by the proctetive environment of MSV and SBA-15. Such an Hb-mesoporous support with high Hb immobilization capacity, high activity, and enhanced thermal stability will be attractive for practical applications.

A New X-Ray Diffraction Method for Quantitative Multicomponent Analysis

1973 ◽  
Vol 17 ◽  
pp. 106-115 ◽  
Author(s):  
Frank H. Chung
Keyword(s):  
Calibration Curve ◽  
Fundamental Matrix ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Absorption Effect ◽  
Multicomponent Analysis ◽  
X Ray ◽  
Practical Applications ◽  
The Matrix

AbstractA unified matrix-flushing theory and its practical applications for quantitative multicomponent analysis by X-ray diffraction are presented.In this method, a fundamental “matrix-flushing” concept is introduced; the calibration curve procedure is shunted; the matrix (absorption) effect is totally eliminated; all components, crystalline or amorphous, can be determined.

X-Ray Diffraction Phase Analysis Using Microcomputers

1981 ◽  
Vol 25 ◽  
pp. 237-244
Author(s):  
T. M. Hare ◽  
J. C. Russ ◽  
M. J. Lanzo
Keyword(s):  
Large Data ◽  
Floppy Disk ◽  
Limited Range ◽  
X Ray Diffraction ◽  
Data Bases ◽  
X Ray ◽  
Practical Applications ◽  
Intelligent Terminal ◽  
Time Share ◽  
Pattern Information

X-ray diffraction to determine the phases present in complex specimens generally proceeds by acquiring a pattern of D-spacings and intensities from the sample, which is then compared to patterns from a series of known or standard phases. The process of searching through large data bases to identify matches is too time consuming for manual methods, and so computerised search/match programs have come into use. The magnitude of the general problem, in which perhaps 40,000 known patterns (corresponding to the present size of the JCPDS powder diffraction file) are involved, places it in the realm of large nainframe computers, which are often accessible on a time-share basis by many laboratories or researchers using XRD. On the other hand, in many practical applications, the search need only be carried out over a limited range of compounds which are expected or may possibly be present based on the known history of the material, or on its independently determined composition. In this case, the data base becomes much smaller, and can be accommodated In micro- and minicomputers. The system we report here utilizes a 64K-byte 8 -bit microcomputer (Apple 11+) with dual floppy disk drives. One 5-1/4 inch disk can hold the pattern information for fifty compounds, and can be searched for possible matches in a few minutes. The same computer can control the scanning diffractometer to acquire the pattern data, and can act as an intelligent terminal to larger time-share machines when it is necessary to access the large data bases.

scholarly journals Effect of TeO2 addition on the dielectric properties of CaCu3Ti4O12 ceramics derived from the oxalate precursor route

2013 ◽  
Vol 03 (04) ◽  
pp. 1350028 ◽  
Author(s):  
P. Thomas ◽  
K. B. R. Varma
Keyword(s):  
Dielectric Properties ◽  
Dielectric Loss ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
Oxalate Precursor ◽  
X Ray ◽  
Practical Applications ◽  
Low Dielectric ◽  
Precursor Route ◽  
Tan Δ

CaCu 3 Ti 4 O 12 (CCTO) ceramics which has perovskite structure gained considerable attention due to its giant permittivity. But it has high tan δ (0.1 at 1 kHz) at room temperature, which needs to be minimized to the level of practical applications. Hence, TeO 2 which is a good glass former has been deliberately added to CCTO nanoceramic (derived from the oxalate precursor route) to explore the possibility of reducing the dielectric loss while maintaining the high permittivity. The structural, morphological and dielectric properties of the pure CCTO and TeO 2 added ceramics were studied using X-ray diffraction, Scanning Electron Microscope along with Energy Dispersive X-ray Analysis (EDX), spectroscopy and Impedance analyzer. For the 2.0 wt.% TeO 2 added ceramics, there is a remarkable difference in the microstructural features as compared to that of pure CCTO ceramics. This sample exhibited permittivity values as high as 7387 at 10 KHz and low dielectric loss value of 0.037 at 10 kHz, which can be exploited for the high frequency capacitors application.

scholarly journals A Ten-Day Course for Chemical Crystallography

2014 ◽  
Vol 70 (a1) ◽  
pp. C1387-C1387
Author(s):  
Charlotte Stern ◽  
Allen Oliver ◽  
Amy Sarjeant
Keyword(s):  
Black Box ◽  
X Ray Diffraction ◽  
General Curriculum ◽  
X Ray ◽  
Practical Applications ◽  
Core Curricula ◽  
Chemical Crystallography ◽  
Structure Solution ◽  
Hands On ◽  
Intensive Course

Crystallography has long been a subject excluded from core curricula in undergraduate and graduate Chemistry programs. Occasionally offered as an elective or special topics course, crystallography remains a "black box" technique to many researchers who rely on it for verification of their work. Students interested in learning the theory and in-depth practical applications are often left to their own devices and seek out workshops, special courses, or one-on-one training. Currently, the authors host a ten-day intensive course on chemical crystallography, covering theory, hands-on experimental technique, and structure solution and refinement for both single crystal and powder X-ray diffraction. Here we describe the features of the course, the general curriculum and the demographics of attendees and faculty instructors.

scholarly journals A Simple and Facile Solvothermal Synthesis of Hierarchical PbS Microstars with Multidendritic Arms and Their Optical Properties

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Yong-Fang Li ◽  
Ming Zhang ◽  
Qi-Jing Yang ◽  
Feng-Xian Zhang ◽  
Mei-Qi Zheng ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solvothermal Synthesis ◽  
Room Temperature ◽  
X Ray Diffraction ◽  
X Ray ◽  
Practical Applications ◽  
Solar Absorbers ◽  
Transmission Electron ◽  
Ir Photodetectors ◽  
Ft Ir

A simple and facile approach was developed in the solvothermal synthesis of hierarchical PbS microstars with multidendritic arms, which were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR) and photoluminescence (PL) spectroscopy. The morphologies of PbS products were strongly determined by the reaction time and temperature, the ratios of the precursors, and the mixed solvent with various components, and thereby their possible formation mechanism was discussed in some detail. The as-prepared PbS crystals displayed a sharp and strong photoluminescent peak at 437 nm at room temperature. It has potential and practical applications in photoluminescence, photovoltaics, IR photodetectors, electroluminescence, and solar absorbers.

X-Ray Induced Insulator-Metal Transitions in CMR Manganites

1997 ◽  
Vol 494 ◽  
Author(s):  
V. Kiryukhin ◽  
D. Casa ◽  
B. Keimer ◽  
J. P. Hill ◽  
A. Vigliante ◽  
...  
Keyword(s):  
Lattice Structure ◽  
Charge Ordering ◽  
X Ray Diffraction ◽  
Temperature Dependent ◽  
X Ray ◽  
Practical Applications ◽  
Transitional State ◽  
Current Voltage ◽  
Highly Nonlinear ◽  
Type Of Transition

ABSTRACTIn this work we report a study of the photoinduced insulator-to-metal transition in manganese oxide perovskites of the formula Pr1-xCaxMnO3. The transition is closely related to the magnetic field induced insulator-to-metal transition (CMR effect) observed in these materials. It is accompanied by a dramatic change in the magnetic properties and lattice structure: the material changes from an insulating charge-ordered canted antiferromagnet to a ferromagnetic metal. We present an investigation of the transport and structural properties of these materials over the course of the transition (which usually takes about an hour to complete). The current-voltage characteristics exhibited by the material during the transition are highly nonlinear, indicating a large inhomogeneity of the transitional state. Possible practical applications of this novel type of transition are briefly discussed. We also report a high-resolution x-ray diffraction study of the charge-ordering in these materials. The temperature dependent charge ordering structure observed in these compounds is more complex than previously reported.

NEW 1222-TYPE LAYERED CUPRATES (Tl,M)Sr2(Nd,Ce)2Cu2Oz(M = Ti or Nb)

1992 ◽  
Vol 06 (16n17) ◽  
pp. 1019-1023 ◽  
Author(s):  
Z. Y. CHEN ◽  
Z. Z. SHENG ◽  
Y. Q. TANG ◽  
Y. F. LI ◽  
D. O. PEDERSON
Keyword(s):  
Lattice Parameters ◽  
Pure Form ◽  
X Ray Diffraction ◽  
X Ray ◽  
Layered Cuprates

New 1222-type layered cuprates (Tl,M)Sr 2 (Nd,Ce) 2 Cu 2 O z (M = Ti or Nb) have been successfully synthesized in the pure form and identified by powder X-ray diffraction analyses. The lattice parameters are a=3.847 Å and c=29.43 Å for ( Tl 0.8 Ti 0.2) Sr 2( Nd 0.75 Ce 0.25)2- Cu 2 O 9 and a=3.852 Å and c=29.45 Å for ( Tl 0.8 Nb 0.2) Sr 2( Nd 0.75 Ce 0.25)2 Cu 2 O 9. Resistance measurements showed that they me superconducting at about 40 K.

FACILE SYNTHESIS OF HYDROXYLAPATITE NANOSTRUCTURES WITH VARIOUS MORPHOLOGIES

NANO ◽  
2009 ◽  
Vol 04 (03) ◽  
pp. 165-170 ◽  
Author(s):  
XIAO-JUN HU ◽  
JIN-KU LIU ◽  
XIAO-YAN QIN ◽  
JIA HUANG ◽  
YI YI
Keyword(s):  
Crystal Engineering ◽  
Fourier Transforms ◽  
X Ray Diffraction ◽  
X Ray ◽  
Solution Approach ◽  
Engineering Research ◽  
Practical Applications ◽  
Transmission Electron ◽  
Ft Ir ◽  
Fourier Transforms Infrared Spectroscopy

The hydroxylapatite nanostructures with different morphologies have been synthesized by a facile solution approach. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) technologies, and Fourier transforms infrared spectroscopy (FT-IR). The control mechanism of the hydroxylapatite with various morphologies nanostructures was investigated. Some practical experimental conclusions could be obtained, which were expected to have potential values in crystal engineering research and practical applications.

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