Quantitative studies of domain evolution in tetragonal BS–PT ceramics in electric poling and thermal depoling processes

2019 ◽  
Vol 7 (15) ◽  
pp. 4517-4526 ◽  
Author(s):  
Jingen Wu ◽  
Xiangyu Gao ◽  
Yang Yu ◽  
Jikun Yang ◽  
Zhaoqiang Chu ◽  
...  
Keyword(s):  
Poling Process ◽  
Domain Evolution ◽  
Quantitative Studies

In the electric poling process, 180° and 90° domain reversals in tetragonal BS–PT ceramics are quantitatively estimated based on their charge contributions.

Observation of the Poling Process in Ferroelectric Ceramics Using Piezoresponse Force Microscopy

2012 ◽  
Author(s):  
K. L. Kim ◽  
J. E. Huber
Keyword(s):  
Electric Field ◽  
Domain Structure ◽  
Piezoresponse Force Microscopy ◽  
Ferroelectric Materials ◽  
Ferroelectric Ceramics ◽  
Pixel Intensity ◽  
Poling Process ◽  
Force Microscopy ◽  
Domain Evolution ◽  
Domain Structures

Evolution of the domain structure in bulk polycrystalline PZT during poling was studied using Piezoresponse Force Microscopy (PFM). For the study, two different experimental methods were employed. First, a trapezoidal PZT specimen was subjected to electric field so as to produce a wide variation of electric field intensity in the specimen. PFM images were then acquired from several different areas that have experienced different field strengths. Histograms of pixel intensity show a distinct difference in the pattern of piezoresponse signal between poled and unpoled areas. The presence of non-180° domain structure in the scanned area significantly affects the histogram pattern. At high levels of electric field the presence of mainly 180° domain structures leads to a bi-modal M-shaped histogram. To illustrate the evolution of the non-180° domain structure, in-plane poling was conducted with the electric field level increased in steps, and the domain evolution process was observed by PFM after each step. The resulting images demonstrate that non-180° domain structures gradually disappear from the specimen surface during the poling process. The PFM data can be exploited to study domain evolution in bulk ferroelectric materials via both qualitative observation and statistical analysis.

Residual Gas Reaction in the Electron Microscope: II The Design of a Gas-Control Chamber for Quantitative Observations

1969 ◽  
Vol 27 ◽  
pp. 82-83
Author(s):  
Chester J. Calbick ◽  
Richard E. Hartman
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Local Environment ◽  
Chamber Pressure ◽  
Objective Lens ◽  
Ion Pump ◽  
Quantitative Studies ◽  
Precise Knowledge ◽  
Differential Pumping ◽  
And Control

Quantitative studies of the phenomenon associated with reactions induced by the electron beam between specimens and gases present in the electron microscope require precise knowledge and control of the local environment experienced by the portion of the specimen in the electron beam. Because of outgassing phenomena, the environment at the irradiated portion of the specimen is very different from that in any place where gas pressures and compositions can be measured. We have found that differential pumping of the specimen chamber by a 4" Orb-Ion pump, following roughing by a zeolite sorption pump, can produce a specimen-chamber pressure 100- to 1000-fold less than that in the region below the objective lens.

Comparative strengths and weaknesses of peroxidase and colloidal gold in pre- and post-embedding immunolabeling techniques

1987 ◽  
Vol 45 ◽  
pp. 1002-1005
Author(s):  
D. R. Abrahamson ◽  
P. L. St.John ◽  
E. W. Perry
Keyword(s):  
Electron Microscopy ◽  
Horseradish Peroxidase ◽  
Light Microscopy ◽  
Colloidal Gold ◽  
Light Microscope ◽  
Ultrastructural Localization ◽  
The Other ◽  
Quantitative Studies ◽  
Dense Suspension ◽  
Antigen Localization

Antibodies coupled to tracers for electron microscopy have been instrumental in the ultrastructural localization of antigens within cells and tissues. Among the most popular tracers are horseradish peroxidase (HRP), an enzyme that yields an osmiophilic reaction product, and colloidal gold, an electron dense suspension of particles. Some advantages of IgG-HRP conjugates are that they are readily synthesized, relatively small, and the immunolabeling obtained in a given experiment can be evaluated in the light microscope. In contrast, colloidal gold conjugates are available in different size ranges and multiple labeling as well as quantitative studies can therefore be undertaken through particle counting. On the other hand, gold conjugates are generally larger than those of HRP but usually can not be visualized with light microscopy. Concern has been raised, however, that HRP reaction product, which is exquisitely sensitive when generated properly, may in some cases distribute to sites distant from the original binding of the conjugate and therefore result in spurious antigen localization.

Understanding Why Older People Develop a Wish to Die

Crisis ◽  
2011 ◽  
Vol 32 (4) ◽  
pp. 204-216 ◽  
Author(s):  
M. L. Rurup ◽  
H. R. W. Pasman ◽  
J. Goedhart ◽  
D. J. H. Deeg ◽  
A. J. F. M. Kerkhof ◽  
...  
Keyword(s):  
Older People ◽  
Cohort Studies ◽  
Conceptual Framework ◽  
Life Events ◽  
Traumatic Life Events ◽  
Quantitative Studies ◽  
Wish To Die ◽  
Open Coding ◽  
Death Wishes ◽  
Depth Interviews

Background: Quantitative studies in several European countries showed that 10–20% of older people have or have had a wish to die. Aims: To improve our understanding of why some older people develop a wish to die. Methods: In-depth interviews with people with a wish to die (n = 31) were carried out. Through open coding and inductive analysis, we developed a conceptual framework to describe the development of death wishes. Respondents were selected from two cohort studies. Results: The wish to die had either been triggered suddenly after traumatic life events or had developed gradually after a life full of adversity, as a consequence of aging or illness, or after recurring depression. The respondents were in a situation they considered unacceptable, yet they felt they had no control to change their situation and thus progressively “gave up” trying. Recurring themes included being widowed, feeling lonely, being a victim, being dependent, and wanting to be useful. Developing thoughts about death as a positive thing or a release from problems seemed to them like a way to reclaim control. Conclusions: People who wish to die originally develop thoughts about death as a positive solution to life events or to an adverse situation, and eventually reach a balance of the wish to live and to die.

QUANTITATIVE STUDIES OF IODINE METABOLISM IN SPORADIC, NON-TOXIC GOITRE

1974 ◽  
Vol 76 (1) ◽  
pp. 67-73 ◽  
Author(s):  
H. Agerbæk ◽  
S. E. Jensen
Keyword(s):  
Iodine Deficiency ◽  
Iodine Uptake ◽  
Quantitative Studies ◽  
Euthyroid State ◽  
Iodine Metabolism ◽  
Dynamic Patterns ◽  
Perchlorate Discharge Test ◽  
Normal Controls ◽  
Discharge Test

ABSTRACT In 129 patients with non-toxic goitre and 27 normal controls, thyroid dynamic patterns were estimated in an attempt to elucidate pathogenesis. The clinically euthyroid state was confirmed by measurement of PBI, T3-sephadex uptake and BMR. Thyroid clearance (th. cl.), plasma iodide (PII), and absolute iodine uptake (AIU) were determined and a perchlorate discharge test performed. Twenty patients (16%) had a high AIU and were thus suspected of having dyshormonogenesis; nine were thoroughly investigated and in six dyshormonogenesis was found. Both normals and non-toxic goitre patients had a low PII, but in the goitrous patients values were lowest. The thyroid clearance of iodide was significantly higher in the goitre patients, suggesting iodine deficiency to be a major aetiologic factor for goitre formation. AIU was higher in the goitre patients than in normals, suggesting a larger iodine leakage from the thyroid in these patients.

Antecedents of Family Conflict in Uganda

2020 ◽  
Vol 12 (3) ◽  
pp. 35-54
Author(s):  
Rogers Matama ◽  
Kezia H. Mkwizu
Keyword(s):  
Content Analysis ◽  
Social Identity ◽  
Sample Size ◽  
Social Identity Theory ◽  
Family Conflict ◽  
Qualitative Approach ◽  
Future Research ◽  
Family Conflicts ◽  
The Core ◽  
Quantitative Studies

The purpose of this study was to explore the antecedents of family conflict in Uganda. A qualitative approach was used in this study. A sample size of 139 participants provided data which was subjected to content analysis. Results revealed that the core themes associated with family conflict are finances and priority of resources. Further findings show that differences in tastes and interests, selfishness and lack of communication played a key role as causes of family conflicts. The implication of this study is that finances and priority of resources are antecedents of family conflict in the context of Uganda. Therefore, the antecedents of family conflict that emerged from this study can be understood, defined and analyzed through the lens of social identity theory. Future research may include conducting quantitative studies with a particular demographic using the themes that have emerged from this study.

The Quantitative Studies on the Connective NPs

HAN-GEUL ◽  
2005 ◽  
Vol 269 ◽  
pp. 135
Author(s):  
Woon Ho Choi
Keyword(s):  
Quantitative Studies
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