X-ray particle-size broadening

1986 ◽  
Vol 42 (1) ◽  
pp. 6-13 ◽  
Author(s):  
S. Rao ◽  
C. R. Houska
Keyword(s):  
Particle Size ◽  
Normal Distribution ◽  
Variation Coefficient ◽  
Column Height ◽  
X Ray Diffraction ◽  
Diffraction Profile ◽  
X Ray ◽  
The Mean ◽  
Log Normal ◽  
Log Normal Distribution

X-ray diffraction profiles and Fourier coefficients are given for particles distributed according to experimentally verified size distributions. Calculations are based upon the log normal distribution of sphere diameters and intercept lengths in addition to a normal distribution of column heights. It is found that the diffraction profile is not sensitive to the fine details of the distribution but rather the mean column height and the column-height variation coefficient. Errors in particle-size determinations will result from an improper choice of the variation coefficient. Two simplified models are given that describe the diffraction profiles for a large range of variation coefficients.

Determination of particle size distribution in an Fe2O3-based catalyst using magnetometry and x-ray diffraction

1992 ◽  
Vol 7 (7) ◽  
pp. 1856-1860 ◽  
Author(s):  
Manjula M. Ibrahim ◽  
Jianmin Zhao ◽  
Mohindar S. Seehra
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mössbauer Measurements ◽  
Log Normal ◽  
Log Normal Distribution

In this paper, the techniques of SQUID magnetometry and line broadening in x-ray diffraction are employed for determining an important parameter for catalysts, viz. the particle size distribution. Magnetization versus temperature (5 K–400 K) and magnetization versus field (up to 55 kOe) data are reported for an α–Fe2O3 based catalyst. After determining the region of superparamagnetism, the distribution function f(r) is determined assuming a log normal distribution and Langevin paramagnetism of superparamagnetic particles. The distribution is found to be fairly symmetric with center near 65 Å and range of 35 to 115 Å. From line-broadening of Bragg peaks in x-ray diffraction, particle radii varying between 75 Å and 110 Å are obtained. These results are compared with the reported Mössbauer measurements of Huffman et al. on the same sample.

Determination of Particle Size of a Dispersed Phase by Small-Angle X-ray Scattering

1989 ◽  
Vol 171 ◽  
Author(s):  
Frank C. Wilson
Keyword(s):  
Particle Size ◽  
High Resolution ◽  
Spherical Particles ◽  
Dispersed Phase ◽  
X Ray ◽  
X Ray Scattering ◽  
Resultant Data ◽  
Log Normal ◽  
Log Normal Distribution

ABSTRACTA method for determining particle diameters up to ca 500 rnm is described. X-ray data are obtained with an ultra-high resolution Bonse-Hart diffractometer and subsequently desmeared. The resultant data, viewed as the invariant argument h l(h), are interpreted as arising from a log-normal distribution of independent spherical particles. The distribution is characterized by its median value and breadth.

Characterization of Ni Nanopowders Produced by Electrical Explosion of Wire Technique

2006 ◽  
Vol 510-511 ◽  
pp. 710-713
Author(s):  
Hwan Tae Kim ◽  
Won Sik Seo ◽  
Dae Hwan Kwon ◽  
Pyuck Pa Choi ◽  
Ji Soon Kim ◽  
...  
Keyword(s):  
Particle Size ◽  
Electrical Explosion ◽  
Nickel Wire ◽  
X Ray Diffraction ◽  
Nitrogen Gas ◽  
Argon Gas ◽  
X Ray ◽  
Nickel Powders ◽  
The Mean

Nanosize nickel powders were successfully produced by electrical explosion of wire (EEW). In EEW, the nickel wire was discharged in a chamber filled with nitrogen or argon gas, and the produced powders were subsequently stabilized by air-passivation at room temperature for 2 h. X-ray diffraction only showed the nickel phase of FCC crystal structure, whereas TEM and XPS analyses showed the formation of a very thin oxide layer of NiO on the surface of particles. Particles were spherical in shape, and the mean particle size calculated by specific surface area was about 100 nm. The particle size decreased with increasing charging voltage and with increasing ambient gas pressure. Argon gas was more effective in producing finer particles than nitrogen gas.

Three-beam X-ray diffraction – profile analysis

2003 ◽  
Vol 36 (6) ◽  
pp. 1324-1333 ◽  
Author(s):  
Gunnar Thorkildsen ◽  
Helge B. Larsen ◽  
Edgar Weckert ◽  
Dag Semmingsen
Keyword(s):  
Profile Analysis ◽  
Domain Size ◽  
Incoherent Scattering ◽  
Secondary Beam ◽  
X Ray Diffraction ◽  
Diffraction Profile ◽  
X Ray ◽  
Oxalic Acid Dihydrate ◽  
The Mean ◽  
Beam Interaction

An original functional description of the intensity perturbation of the two-beam diffracted power caused by an interfering three-beam interaction has been developed. By using this approach in the analysis of measured three-beam profiles of α-oxalic acid dihydrate, parameters related to the Darwin mosaic model are refined. The final results indicate an anisotropy in both the mean domain size, measured along the secondary beam, and the block orientation, measured as the angular spread in the location of the three-beam point. The presented method relies on a procedure for merging the contributions to the perturbation originating from dynamical (coherent) and kinematical (incoherent) scattering processes.

scholarly journals Estimating the mean and variance from the five-number summary of a log-normal distribution

2020 ◽  
Vol 13 (4) ◽  
pp. 519-531
Author(s):  
Jiandong Shi ◽  
Tiejun Tong ◽  
Yuedong Wang ◽  
Marc G. Genton
Keyword(s):  
Normal Distribution ◽  
Mean And Variance ◽  
The Mean ◽  
Log Normal ◽  
Log Normal Distribution

Preparation and Characterization of Lignin Powder Micronized by a Supercritical Antisolvent (SAS) Process

2011 ◽  
Vol 233-235 ◽  
pp. 1642-1645 ◽  
Author(s):  
Qi Lu ◽  
Yuan Gang Zu ◽  
Lei Yang ◽  
Xiu Hua Zhao ◽  
Wen Jun Liu ◽  
...  
Keyword(s):  
Particle Size ◽  
Optimal Conditions ◽  
Orthogonal Array Design ◽  
X Ray Diffraction ◽  
Array Design ◽  
X Ray ◽  
Mean Particle Size ◽  
Supercritical Antisolvent ◽  
The Mean

Nanoscale lignin was successfully prepared with a supercritical antisolvent (SAS) apparatus using acetone as a solvent and superciritical carbon dioxide as an antisolvent. Four factors were studied and optimized by a four-level orthogonal array design (OAD). According to analysis of variance, precipitation pressure had a significant effect on mean particle size. The optimal conditions are as follows: precipitation temperature 35 °C, precipitation pressure 30 MPa, temperature difference +10 °C and concentration of lignin solution 0.5 mg/mL. The micronized lignin under the optimal conditions was characterized by Scanning Electron Microscopy (SEM), Fourier-transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS) and X-Ray Diffraction (XRD) analyses. The results showed the mean particle size of micronized lignin was 0.144 ± 0.03 μm and had no degradation. The solubility of micronized lignin was improved significantly in distilled water.

Sign in / Sign up

Export Citation Format

Share Document