Isotope shift in the NMR of iron

1969 ◽  
Vol 47 (6) ◽  
pp. 697-698 ◽  
Author(s):  
B. G. Turrell
Keyword(s):  
Isotope Shift ◽  
Zero Field ◽  
Previous Estimate ◽  
Two Samples ◽  
Isotopic Constitution

The zero-field NMR frequencies of two samples of iron with different isotopic constitution have been compared at various temperatures. An isotope shift is observed which is different from a previous estimate. A possible explanation for the isotope shift is suggested.

scholarly journals Tailoring Interfacial Exchange Anisotropy in Hard–Soft Core-Shell Ferrite Nanoparticles for Magnetic Hyperthermia Applications

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 262
Author(s):  
Venkatesha Narayanaswamy ◽  
Imaddin A. Al-Omari ◽  
Aleksandr S. Kamzin ◽  
Bashar Issa ◽  
Ihab M. Obaidat
Keyword(s):  
Magnetic Hyperthermia ◽  
Ferrite Nanoparticles ◽  
Soft Core ◽  
Core Shell ◽  
Zero Field ◽  
Exchange Anisotropy ◽  
Shell Nanoparticles ◽  
Heating Efficiency ◽  
Two Samples ◽  
Core Shell Nanoparticles

Magnetically hard–soft core-shell ferrite nanoparticles are synthesized using an organometallic decomposition method through seed-mediated growth. Two sets of core-shell nanoparticles (S1 and S2) with different shell (Fe3O4) thicknesses and similar core (CoFe2O4) sizes are obtained by varying the initial quantities of seed nanoparticles of size 6.0 ± 1.0 nm. The nanoparticles synthesized have average sizes of 9.5 ± 1.1 (S1) and 12.2 ± 1.7 (S2) nm with corresponding shell thicknesses of 3.5 and 6.1 nm. Magnetic properties are investigated under field-cooled and zero-field-cooled conditions at several temperatures and field cooling values. Magnetic heating efficiency for magnetic hyperthermia applications is investigated by measuring the specific absorption rate (SAR) in alternating magnetic fields at several field strengths and frequencies. The exchange bias is found to have a nonmonotonic and oscillatory relationship with temperature at all fields. SAR values of both core-shell samples are found to be considerably larger than that of the single-phase bare core particles. The effective anisotropy and SAR values are found to be larger in S2 than those in S1. However, the saturation magnetization displays the opposite behavior. These results are attributed to the occurrence of spin-glass regions at the core-shell interface of different amounts in the two samples. The novel outcome is that the interfacial exchange anisotropy of core-shell nanoparticles can be tailored to produce large effective magnetic anisotropy and thus large SAR values.

ZERO FIELD EXCESS CONDUCTIVITY STUDIES IN THE Bi-Sr-Ca-Cu-O SYSTEM

1992 ◽  
Vol 06 (29) ◽  
pp. 1857-1865 ◽  
Author(s):  
S. RAVI ◽  
V. SESHU BAI
Keyword(s):  
Mean Field ◽  
Excess Conductivity ◽  
Zero Field ◽  
Pair Breaking ◽  
Field Region ◽  
Average Value ◽  
Two Samples ◽  
The Mean ◽  
Breaking Time

The excess conductivity (∆σ) data on several samples of 85 K phase and 110 K phase of Bi-Sr-Ca-Cu-O system were fitted to a sum of direct (AL) and indirect (MT) contribution of fluctuation induced excess conductivity, in the mean field region. The samples of the 85 K phase are of compositions Bi2Sr2CaCu2Oy, Bi2Sr2CaCu2Ag0.8Oy, and Bi2Sr2.14Ca0.86Cu2Oy with Tc (zero) of 78.9 K, 86.5 K and 81.8 K respectively. The two samples of 110 K phase with composition Bi1.2Pb0.3Sr1.5Ca2Cu3Oy were prepared from nitrate and citrate routes respectively and have Tc (zero) of 105.3 K and 102.9 K. We find from our analysis relatively strong pair-breaking effects in both 85 K and 110 K phases, indicating the contribution of Maki-Thompson term to the excess conductivity to be rather insignificant. The average value estimated for the phase-breaking time for the 85 K and 110 K phases are (3.7±0.5)×10−16s and(11.3±1.6)×10−16s respectively, at 100 K.

Electron energy-loss near-edge structure in silicate minerals

1992 ◽  
Vol 50 (2) ◽  
pp. 1258-1259
Author(s):  
D W McComb ◽  
R S Payne ◽  
P L Hansen ◽  
R Brydson
Keyword(s):  
Solid State ◽  
Energy Loss ◽  
Electron Energy ◽  
State Energy ◽  
Local Environment ◽  
Edge Structure ◽  
Silicate Minerals ◽  
Two Samples ◽  
Electron Energy Loss ◽  
Careful Processing

Electron energy-loss near-edge structure (ELNES) is an effective probe of the local geometrical and electronic environment around particular atomic species in the solid state. Energy-loss spectra from several silicate minerals were mostly acquired using a VG HB501 STEM fitted with a parallel detector. Typically a collection angle of ≈8mrad was used, and an energy resolution of ≈0.5eV was achieved.Other authors have indicated that the ELNES of the Si L2,3-edge in α-quartz is dominated by the local environment of the silicon atom i.e. the SiO4 tetrahedron. On this basis, and from results on other minerals, the concept of a coordination fingerprint for certain atoms in minerals has been proposed. The concept is useful in some cases, illustrated here using results from a study of the Al2SiO5 polymorphs (Fig.l). The Al L2,3-edge of kyanite, which contains only 6-coordinate Al, is easily distinguished from andalusite (5- & 6-coordinate Al) and sillimanite (4- & 6-coordinate Al). At the Al K-edge even the latter two samples exhibit differences; with careful processing, the fingerprint for 4-, 5- and 6-coordinate aluminium may be obtained.

Effect of thermal annealing on grain boundary chemistry of polycrystalline TiBa2Ca2Cu3Oy films

1994 ◽  
Vol 52 ◽  
pp. 968-969
Author(s):  
Z. L. Wang ◽  
C. L. Briant ◽  
J. DeLuca ◽  
A. Goyal ◽  
D. M. Kroeger ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Weak Link ◽  
Zero Field ◽  
Stabilized Zirconia ◽  
Local Texture ◽  
Transmission Electron ◽  
Axis Alignment ◽  
Boundary Chemistry ◽  
Small Misorientation ◽  
Misorientation Angles

Recent studies have shown that spray-pyrolyzed films of the Tl-1223 compound (TlxBa2Ca2Cu3Oy, with 0.7 < × < 0.95) on polycrystalline yttrium stabilized zirconia substrates can be prepared which have critical current density Jc near 105 A/cm2 at 77 K, in zero field. The films are polycrystalline, have excellent c-axis alignment, and show little evidence of weak-link behavior. Transmission electron microscopy (TEM) studies have shown that most grain boundaries have small misorientation angles. It has been found that the films have a nigh degree of local texture indicative of colonies of similarly oriented grains. It is believed that inter-colony conduction is enhanced by a percolative network of small angle boundaries at colony interfaces. It has also been found that Jc is increased by a factor of 4 - 5 after the films were annealed at 600 °C in oxygen. This study is thus carried out to determine the effect on grain boundary chemistry of the heat treatment.

Correlating the axial Zero Field Splitting with the slow magnetic relaxation in GdIII SIMs

2021 ◽  
Author(s):  
Júlia Mayans ◽  
Albert Escuer
Keyword(s):  
Magnetic Relaxation ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Slow Magnetic Relaxation

A possible relation between the value of the axial Zero Field Splitting and the occurrence of field-induced slow magnetic relaxation has been established for a new gadolinium(iii) compound.

Mental representation of economic crisis in Italian and Swiss samples 1The authors would like to thank Maurizio Mistri for his help in the construction of items. This research was supported by a grant from the Italian Murst (ex 40%).

2001 ◽  
Vol 60 (1) ◽  
pp. 11-14 ◽  
Author(s):  
Lucia Savadori ◽  
Eraldo Nicotra ◽  
Rino Rumiati ◽  
Roberto Tamborini
Keyword(s):  
Economic Crisis ◽  
Mental Representation ◽  
Mental Representations ◽  
Social Contexts ◽  
Raw Material ◽  
National Context ◽  
Cluster Procedure ◽  
Total N ◽  
Two Samples ◽  
Important Symptom

The content and structure of mental representation of economic crises were studied and the flexibility of the structure in different social contexts was tested. Italian and Swiss samples (Total N = 98) were compared with respect to their judgments as to how a series of concrete examples of events representing abstract indicators were relevant symptoms of economic crisis. Mental representations were derived using a cluster procedure. Results showed that the relevance of the indicators varied as a function of national context. The growth of unemployment was judged to be by far the most important symptom of an economic crisis but the Swiss sample judged bankruptcies as more symptomatic than Italians who considered inflation, raw material prices and external accounts to be more relevant. A different clustering structure was found for the two samples: the locations of unemployment and gross domestic production indicators were the main differences in representations.

Men Are Hierarchical, Women Are Egalitarian: An Implicit Gender Stereotype

2004 ◽  
Vol 63 (2) ◽  
pp. 107-111 ◽  
Author(s):  
Marianne Schmid Mast
Keyword(s):  
Empirical Evidence ◽  
Implicit Association Test ◽  
Gender Stereotype ◽  
Association Test ◽  
Implicit Association ◽  
Two Samples

The goal of the present study was to provide empirical evidence for the existence of an implicit hierarchy gender stereotype indicating that men are more readily associated with hierarchies and women are more readily associated with egalitarian structures. To measure the implicit hierarchy gender stereotype, the Implicit Association Test (IAT, Greenwald et al., 1998) was used. Two samples of undergraduates (Sample 1: 41 females, 22 males; Sample 2: 35 females, 37 males) completed a newly developed paper-based hierarchy-gender IAT. Results showed that there was an implicit hierarchy gender stereotype: the association between male and hierarchical and between female and egalitarian was stronger than the association between female and hierarchical and between male and egalitarian. Additionally, men had a more pronounced implicit hierarchy gender stereotype than women.

Question Wording Effects in the Assessment of Global Self-Esteem

2000 ◽  
Vol 16 (1) ◽  
pp. 13-19 ◽  
Author(s):  
Martin Dunbar ◽  
Graeme Ford ◽  
Kate Hunt ◽  
Geoff Der
Keyword(s):  
Reading Ability ◽  
Factor Model ◽  
Self Esteem ◽  
Reading Scores ◽  
Poor Reading ◽  
Method Effect ◽  
Two Samples ◽  
Positive Item ◽  
Method Effects ◽  
Best Fit

Summary: Marsh (1996) produced evidence that method effects associated with negatively worded items might be responsible for the results of earlier factor analytic studies that reported finding positive and negative self-esteem factors in the Rosenberg Global self-esteem scale ( Rosenberg, 1965 ). He analyzed data collected from children using a 7-item self-esteem measure. This report details attempts to replicate Marsh 's analysis in data collected from two samples of adults who completed the full 10-item Global Self-Esteem (GSE) scale. The results reported here are similar to those given by Marsh in so much as a correlated uniquenesses model produced a superior fit to the data than the simple one factor model (without correlated uniquenesses) or the often reported two factor (positive and negative self-esteem) model. However, whilst Marsh reported that the best fit was produced by allowing negative item uniquenesses to correlate with each other, the model that produced the best fit to these data was one that contained correlated positive item uniquenesses. Supporting his claim that differential responding to negative and positive self-esteem items reflects a method effect associated with reading ability, Marsh also showed that factors associated with negative and positive items were most distinct among children who had poor reading scores. We report a similar effect among a sample of older adults where the correlation between these factors was compared across two groups who were selected according to their scores on a test of verbal reasoning.

Spearman's Law of Diminishing Returns

2006 ◽  
Vol 27 (4) ◽  
pp. 199-207 ◽  
Author(s):  
Peter Hartmann
Keyword(s):  
Principal Axis ◽  
Age Groups ◽  
Principal Component ◽  
Longitudinal Survey ◽  
Male And Female ◽  
Two Samples ◽  
Diminishing Returns ◽  
The One ◽  
Armed Services ◽  
Principal Axis Factor

Spearman's Law of Diminishing Returns (SLODR) with regard to age was tested in two different databases from the National Longitudinal Survey of Youth. The first database consisted of 6,980 boys and girls aged 12–16 from the 1997 cohort ( NLSY 1997 ). The subjects were tested with a computer-administered adaptive format (CAT) of the Armed Services Vocational Aptitude Battery (ASVAB) consisting of 12 subtests. The second database consisted of 11,448 male and female subjects aged 15–24 from the 1979 cohort ( NLSY 1979 ). These subjects were tested with the older 10-subtest version of the ASVAB. The hypothesis was tested by dividing the sample into Young and Old age groups while keeping IQ fairly constant by a method similar to the one developed and employed by Deary et al. (1996) . The different age groups were subsequently factor-analyzed separately. The eigenvalue of the first principal component (PC1) and the first principal axis factor (PAF1), and the average intercorrelation of the subtests were used as estimates of the g saturation and compared across groups. There were no significant differences in the g saturation across age groups for any of the two samples, thereby pointing to no support for this aspect of Spearman's “Law of Diminishing Returns.”

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