1,720,973 research outputs found
Advancement of Ferroelectric Al1−xScxN thin films
Full text linkFerroelectricity in wurtzite-type (w-)Al1−xScxN has enabled new opportunities for integrating ferroelectric thin films into memory and neuromorphic devices. As the first known wurtzite-type ferroelectric, AlScN is notable for its compatibility with CMOS and GaN technologies. This thesis investigates the growth and ferroelectric properties of w-Al1−xScxN thin films, emphasizing temperature stability, epitaxy, and doping. Structural properties were studied through X-ray diffraction (XRD), atomic force microscopy, and scanning transmission electron microscopy (S/TEM). In-situ XRD and permittivity measurements showed that the wurtzite phase in Al1−xScxN remains stable up to 1100 °C. Sputter deposition of w-Al1-xScxN on doped n-GaN yielded high-quality epitaxial films with significantly improved (0002) texture. Lattice-matched w-Al0.89Sc0.11N grown by sputter epitaxy achieved a rocking-curve FWHM of ~252 arcsec. High-resolution STEM confirmed the polarity of these films in the bulk. Growing w-Al0.73Sc0.27N on epi-Pt/GaN rather than n-GaN reduced hysteresis asymmetry, leakage, and coercive field values, despite some loss of texture. Further improvements on epitaxial films were achieved by reducing the electrode thickness from 100 nm to 10 nm. Apart from that, ferroelectricity was also demonstrated in ultra-thin (~5 nm) w-Al1−xScxN layers with switching voltages near 1 V, satisfying low-voltage requirements for memory devices. Unlike conventional oxide ferroelectrics, scaling w-Al0.73Sc0.27N thickness caused no clear degradation of polarization or coercive field. Additionally, oxygen doping during sputtering reduced overall leakage without compromising structural quality. Overall, this work advances w-Al1−xScxN toward device-level implementation, particularly in terms of thermal stability, epitaxy, thickness scaling, and doping
Online Child Sexual Abuse Qualitative Exploration Guidelines
No full textThis file contains the qualitative semi-structured guidelines used for conducting in-depth interviews and key informant interviews to explore online child sexual abuse in Bangladesh
INFLUENCE OF SALINE WATER ON GROWTH AND YIELD OF RICE
Full text linkA Thesis
Submitted to the Faculty of Agriculture,
Sher-e-Bangla Agricultural University, Dhaka,
in partial fulfilment of the requirements
for the degree of
MASTER OF SCIENCE (MS)
IN
AGRONOMY
SEMESTER: JANUARY-JUNE, 2018A pot experiment was conducted with two rice varieties viz. BRRI dhan28 and BRRI dhan47 in
the experimental shed of Department of Agronomy, Sher-e-Bangla Agricultural University,
Dhaka during boro season (2017-2018) to determine the effect of different level of salinity on
rice and finding out the comparative performance of two varieties under salinity. Mixture of
fresh water and marine water was used as salinity treatments. Four salinity treatments were used
in this experiment viz. control S
0
(only fresh water), Quarter strength marine water S
1
(Three part
fresh water and one part marine water), Half strength marine water S
2
(half fresh water and half
marine water), Full strength marine water S
3
(only marine water). These mixtures were used for
irrigation purpose throughout the life cycle. Salt stress significantly reduced plant height, number
of tillers hill
-1
, leaf relative water content, number of effective tillers hill
, panicle length,
number of filled grains panicle
-1
, 1000 grain weight, grain yield , straw yield and biological yield
but increased the number of non-effective tiller hill
-1
and unfilled grain panicle
. Leaf relative
water content (RWC) also decreased due to salinity. With rise in salinity level adverse effect of
salinity was more clearly visible. Different growth stages showed different sensitivity to salinity.
In fact, the primitive growth stages, that is, tillering and panicle initiation showed more
sensitivity to salinity than final growth stages (panicle emergence and ripening). Therefore,
irrigation with saline water at the early growth stages has more negative effect on yield and its
components. Between the two varieties used in this experiment BRRI dhan47 performed better
than BRRI dhan28 under salinity stress condition.
-1
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Structural and ferroelectric properties of Al1−xScxN
No full text7199The wurtzite-type solid solutions can be considered the newest class of thin film ferroelectrics available to microelectronics. They are characterized by very high spontaneous polarizations in excess of 100 μC/cm2, excellent retention due to their high coercive fields and straight forward compatibility to silicon and GaN based semiconductor platforms. Their far from common scalability in terms of film thickness over more than 3 orders of magnitude—from below 5 nm to above 500 nm, further make then suitable for a wide variety of applications, from memory to micromechanical sensors and actuators. In this chapter, we give the reader an introduction to the first, and as of now predominant, wurtzite-type ferroelectric: Al1−xScxN. We start by discussing the effect of the chemical composition of the solid solution on the structure of the compound and how the structure simultaneously is also dependent on the deposition process and the underlying growth template. This is followed by a summary of the ferroelectric properties in dependence of Scandium content and stress, their endurance and retention up to temperatures above 1000 °C, while also discussing the main drawback which currently still affects the wurtzite-type ferroelectrics: Their comparable high leakage current in the vicinity and above the coercive field. We conclude by comparing the occurrence of ferroelectricity in Al1−xScxN with other recently confirmed wurtzite-type ferroelectrics.11
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
A Qualitative Analysis of Different Types ofWater Repellent Agent Used on Cotton Fabric
Full text linkThe existence of intermolecular attractive forces of polarity and hydrogen bond is imperative in providing strength, heat resistance and drycleaning resistance to cotton fabric. However, these forces enhance easy wetting of fiber by water offering little resistance to snow and rain for outerwear garments. This problem could be overcome by adding water repellent chemicals to the fabric either chemically or with mechanical coating which prevent penetration of water through the fabric without destroying comfort of the fabric. The aim of the work is to evaluate the effect of different types of water repellent agents used on cotton fabric and analyze different possible factors affecting the performance and quality of treated fabrics. For this purpose, three water repellent chemicals: Lurotex protector RP ECO is a product based on C6 technology, Rucostar EEE6 product consists of a hydrocarbon matrix and hyper-branched, star-shaped polymers(dendrimers) and Nuva TTC is a conventional fluorocarbon based water repellent chemicals were used in three different concentrations to find out an optimum chemical concentration. To judge the quality of the treated fabrics, spray test, air permeability test, strength test and abrasion resistance test were evaluated. The quality of treated fabrics for all three chemicals was very close to each other and if the process parameters is maintained successfully, desired results can be achieved
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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