32 research outputs found
Design aspects of dual gate GaAs nanowire FET for room temperature charge qubit operation: A study on diameter and gate engineering
No full textThe current work explores a geometrically engineered dual gate GaAs nanowire
FET with state of the art miniaturized dimensions for high performance charge
qubit operation at room temperature. Relevant gate voltages in such device can
create two voltage tunable quantum dots (VTQDs) underneath the gates, as well
as can manipulate their eigenstate detuning and the inter-dot coupling to
generate superposition, whereas a small drain bias may cause its collapse
leading to qubit read out. Such qubit operations, i.e., Initialization,
Manipulation, and Measurement, are theoretically modeled in the present work by
developing a second quantization filed operator based Schrodinger-Poisson
self-consistent framework coupled to non-equilibrium Greens function formalism.
The study shows that the Bloch sphere coverage can be discretized along polar
and azimuthal directions by reducing the nanowire diameter and increasing the
inter-dot separation respectively, that can be utilized for selective
information encoding. The theoretically obtained stability diagrams suggest
that downscaled nanowire diameter and increased gate separation sharpen the
bonding and anti-bonding states with reduced anticrossing leading to a gradual
transformation of the hyperbolic current mapping into a pair of straight lines.
However, the dephasing time in the proposed GaAs VTQD-based qubit may be
significantly improved by scaling down both the nanowire diameter and gate
separation. Therefore, the present study suggests an optimization window for
geometrical engineering of a dual gate nanowire FET qubit to achieve superior
qubit performance. Most importantly, such device is compatible with the
mainstream CMOS technology and can be utilized for large scale implementation
by little modification of the state of the art fabrication processes
Linear and non-linear propagation of electron plasma waves in quantum plasma
No full text314-319Using one-dimensional quantum hydrodynamic
model, the linear and non-linear
characteristics of electron plasma waves have been studied both analytically
and numerically in a I two-component
unmagnetized dense quantum plasma with streaming motion. It is shown that
quantum effect modifies the linear dispersion character of the electron plasma
waves and streaming effect makes it possible the excitation of two distinct
modes. To describe the non-linear behaviour, Korteweg de Vries equation is derived by using
the standard reductive perturbation technique and incorporating
quantum-mechanical effects. It is shown that depending on/some critical values of the quantum diffraction
parameter both rarefactive and compressive type of solitons can exist in the
model plasma. The structure of the solitary waves is shown to be significantly
affected by the quantum plasma parameters and streaming motion.</span
Effect of non-thermal electrons and warm negative ions on ion-acoustic solitary waves in multi-component drifting plasma
No full text488-493Using the Sagdeev’s
pseudopotential approach, effects of non-thermal electrons and warm negative
ions on the conditions for existence
and structure of first and second order ion-acoustic solitary waves have been
investigated in a multi-component drifting plasma. It is shown that there
exists a critical concentration of negative ions which decides the existence
and nature of the ion-acoustic solitary waves. It is found that the non-thermal
electrons, the concentration of negative ions and the temperature of negative
ions have significant contributions towards the excitation and structure of the
ion-acoustic solitary waves. The plasma under consideration can support the
formation of compressive, rarefactive as well as W-type solitons with certain
restricted values of plasma parameters. The results are important in the
context of ionospheric and magnetospheric plasmas
বাংলাদেশের টেলিভিশন নাটকে নারীর পরিবেশনা: একটি বিচারমূলক পাঠ
No full textবর্তমানে আধুনিক সংস্কৃতির অবিচ্ছেদ্য অঙ্গ ও কেন্দ্রীয় গুরুত্বপূর্ণ নির্ধারক হিসেবে টেলিভিশন তার উপস্থিতি জাহির করে চলেছে। বিশেষ করে টিভি অনুষ্ঠানগুলোর মধ্যে বর্তমানে যেটিতে মানুষ বুঁদ হয়ে থাকছে সেটি হলো ধারাবাহিক নাটক (যা ডেইলি সোপ, মেগাসিরিয়াল কিংবা সিরিয়াল নামে পরিচিত)। প্রাত্যহিক জীবনের কাহিনি নিয়ে নির্মিত এসব নাটক নিজের অজান্তেই মানুষের জীবনের অংশে পরিণত হয়েছে। এ গবেষণায় মূল উদ্দেশ্য হলো বাংলাদেশের ‘পালকি’ ও ‘তুমি আছো তাই’ টেলিভিশন নাটকে নারীকে কীভাবে পরিবেশন করা হয়েছে তা আলোকপাত করা। গবেষণায় আধেয় বিশ্লেষণ পদ্ধতি (Content Analysis Methodology) ব্যবহার করা হয়েছে। এক্ষেত্রে নাটকে নারী বিষয়ক আধেয়কে টেক্সট হিসেবে গণ্য করে এই গবেষণায় গুণগত আধেয় বিশ্লেষণ পদ্ধতির জন্য টেক্সচুয়াল এ্যানালাইসিস নামের বিশ্লেষণ ধারা বেছে নেওয়া হয়েছে। এ গবেষণার ফলাফলে পরিলক্ষিত হয়েছে যে, পালকি ও তুমি আছো তাই নাটকে সমসাময়িক বাংলাদেশের নারীর আধুনিক চরিত্রগুলো দেখানো হয় না, সমাজে নারীর ভূমিকার বাস্তবচিত্রও তুলে ধরা হয় না। নারী পুরুষের চরিত্র নির্মাণের ক্ষেত্রে প্রবল জেন্ডার বৈষম্য লক্ষ্য করা যায়। নারী চরিত্রকে দুর্বল, অধস্তন, পুরুষের উপর নির্ভরশীল, কুটিল নারী হিসেবে পরিবেশন করা হয়েছে। যেখানে নারীরা সর্বদা রোমান্টিক, বৈবাহিক ও পারিবারিক সমস্যা নিয়ে ব্যস্ত থাকে। যদিও খুব সামান্য ক্ষেত্রে ব্যতিক্রম লক্ষ্য করা যায়। এছাড়া নাটকে পুরুষ চরিত্রগুলোকে বিভিন্ন পেশায় দেখা গেলেও নারীকে গৃহকোণনির্ভর ও পেশাহীন করে পরিবেশন করা হয়েছে। ফলে টিভিতে উপস্থাপিত নারী চরিত্রগুলো দিন দিন আতঙ্কিত ও বিরোধের একটি কারণ হয়ে দাঁড়াচ্ছে।</p
Propagation of Electron-Acoustic Solitary Waves in Weakly Relativistically Degenerate Fermi Plasma
No full textUsing one dimensional Quantum hydrodynamic
(QHD) model Korteweg de Vries (KdV) solitary excitations of
electron-acoustic waves (EAWs) have been examined in twoelectron-
populated relativistically degenerate super dense plasma. It
is found that relativistic degeneracy parameter influences the
conditions of formation and properties of solitary structures
Research on Digital Preservation: An empirical analysis
No full textDigital preservation is an evolving area of research for libraries, archives, and museums across the globe over the last two decades. Due to the growing recognition of the need to address various issues dealt with digital preservation, this field of study has generated quite a range of scholarly communications on several aspects. The present paper aims to examine critically the extant literature on digital preservation and libraries for the period from 2001 to 2019 and to assess the evolving trajectory and trends. Out of a total of 1292 extracted records from the Scopus database, a total of 710 articles are considered for the study purpose after the exclusion of non-relevant articles. Employing bibliometric indicators the study primarily assessed the publication pattern, document types, the most prolific authors, most contributing institutions, and focus areas of study as well as the geographical distribution of publications. Along with this, the VOSviewer software is used for co-author network analysis. The findings of the current analysis reveal that the highest number of papers published in the source journal Lecture Notes in Computer Science while the U.S.A. is in the top spot among the countries and author Nelson, M. L. from the U.S.A. has published the maximum number of research papers. It also provides information on various forms of publication on digital preservation and the impactful papers. Though there are studies on the assessment of digital libraries and digital repositories, a bibliometric assessment of literature on digital preservation is a novel attempt. As a metric study, it reflects the relative position of a country, an institution, and a researcher
Genus-level revision of the Alycaeidae (Gastropoda, Cyclophoroidea), with an annotated species catalogue
No full text412 species-group names (including 11 replacement names), and 14 genus-group names of the Alycaeidae have been introduced to date. Type materials of 85% (336) of the known species and subspecies were examined, a further 5% (19) of the taxa were studied using available non-type material, and for another 6% (22) the original descriptions were sufficiently detailed to evaluate their taxonomic status. Only 3% of the taxa (12) could not be examined. Special attention was paid to the sculpture of the embryonic whorls and the sutural tube-microtunnel system in order to provide a novel classification for this group.
In this study 363 taxa (320 species or 43 subspecies) are accepted within the family Alycaeidae. Of these, 22 have been described by the lead author and his coauthors in previous publications. In addition, there are 18 species that were formerly classified in Cycloryx and now belong to Pincerna due to its synonymy with Cycloryx. Among the remaining 323 species, 209 (65%) are transferred here to another genus, whilst 114 (35%) have remained in their original genus.
Seven genera are accepted. While some questions (e.g., the distinction between Pincerna and Alycaeus) remained unanswered, this revision made three main achievements: (1) The Dicharax species were identified based on the absence of spiral striation on the entire shell; (2) the Metalycaeus species were identified based on the spiral striation of the protoconch; (3) and Stomacosmethis was separated from Alycaeus based on the extremely short sutural tube.
Five nominal species are being synonymised with other species, and eight species are now treated as subspecies. The following replacement names are proposed: Dioryx urnula niosiensis Páll-Gergely, nom. nov. for Alycaeus urnula var. daflaensis Godwin-Austen, 1914; Dioryx urnula rotundus Páll-Gergely, nom. nov. for Alycaeus urnula var. globosus Godwin-Austen, 1914; Pincerna crenilabris juttingae Páll-Gergely, nom. nov. for Alycaeus crenilabris laevis van Benthem Jutting, 1959; Pincerna crenilabris korintjiensis Páll-Gergely, nom. nov. for Alycaeus crenilabris latecostatus van Benthem Jutting, 1959; Dicharax conicus jatingaensis Páll-Gergely, nom. nov. for Alycaeus conicus var. nanus Godwin-Austen, 1914; Metalycaeus godwinausteni Páll-Gergely, nom. nov. for Alycaeus neglectus Godwin-Austen, 1914; and finally Metalycaeus suhajdai Páll-Gergely, nom. nov. for Alycaeus varius Godwin-Austen, 1914.Copyright Barna Páll-Gergely et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article.NHM Repositor
Direct verification of the fluctuation-dissipation relation in viscously coupled oscillators
No full text
