2,726 research outputs found
Metastable behavior of vortex matter in the electronic transport processes of homogenous superconductors
We study numerically the effect of vortex pinning on the hysteresis voltage-temperature (V-T) loop of vortex matter. It is found that different types of the V-T loops result from different densities of vortex pinning center. An anticlockwise V-T loop is observed for the vortex system with dense pinning centers, whereas a clockwise V-T loop is brought about for vortices with dilute pinning centers. It is shown that the size of the V-T loop becomes smaller for lower experimental speed, higher magnetic field, or weak pinning strength. Our numerical observation is in good agreement with experiments
History effect in inhomogeneous superconductors
A model was proposed to account for a new kind of history effect in the
transport measurement of a sample with inhomogeneous flux pinning coupled with
flux creep. The inhomogeneity of flux pinning was described in terms of
alternating weak pinning (lower jc) and strong pinning region (higher jc). The
flux creep was characterized by logarithmic barrier. Based on this model, we
numerically observed the same clockwise V-I loops as reported in references.
Moreover, we predicted behaviors of the V-I loop at different sweeping rates of
applied current dI/dt or magnetic fields Ba, etc. Electric transport
measurement was performed in Ag-sheathed Bi2-xPbxSr2Ca2Cu3Oy tapes immersed in
liquid nitrogen with and without magnetic fields. V-I loop at certain dI/dt and
Ba was observed. It is found that the area of the loop is more sensitive to
dI/dt than to Ba, which is in agreement well with our numerical results.Comment: To appear in Phys Rev B, October 1 Issu
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Effect of Second-Phase Doping on Laser Deposited Al2O3 Ceramics
Direct fabrication of engineering ceramic components by additive manufacturing (AM) is a
relatively new method for producing complex mechanical structures. This study investigates how
a second-phase doping may affect Al2O3 ceramic parts deposited by AM with a laser engineered
net shaping (LENS) system. In this study, ZrO2 and Y2O3 powders are respectively doped into
Al2O3 powders at the eutectic ratio as second-phases to improve the quality of a deposited part.
The deposited Al2O3, Al2O3/ZrO2 and Al2O3/YAG (yttrium aluminum garnet) parts are examined
for their micro-structures and micro-hardness, as well as defects. The results show that doping of
ZrO2 or Y2O3 as a second-phase performs a significant role in suppressing cracks and in refining
grains of the laser deposited parts. The micro-hardness investigation reveals that the
second-phase doping does not result in much hardness reduction in Al2O3 and the two eutectic
ceramics are both harder than 1500 Hv. The study concludes that the second-phase doping is
good for improving laser deposited ceramic parts.Mechanical Engineerin
A Critical Analysis Of The State-Of-The-Art On Automated Detection Of Deceptive Behavior In Social Media
Recently, a large body of research has been devoted to examine the user behavioral patterns and the business implications of social media. However, relatively little research has been conducted regarding users’ deceptive activities in social media; these deceptive activities may hinder the effective application of the data collected from social media to perform e-marketing and initiate business transformation in general. One of the main contributions of this paper is the critical analysis of the possible forms of deceptive behavior in social media and the state-of-the-art technologies for automated deception detection in social media. Based on the proposed taxonomy of major deception types, the assumptions, advantages, and disadvantages of the popular deception detection methods are analyzed. Our critical analysis shows that deceptive behavior may evolve over time, and so making it difficult for the existing methods to effectively detect social media spam. Accordingly, another main contribution of this paper is the design and development of a generic framework to combat dynamic deceptive activities in social media. The managerial implication of our research is that business managers or marketers will develop better insights about the possible deceptive behavior in social media before they tap into social media to collect and generate market intelligence. Moreover, they can apply the proposed adaptive deception detection framework to more effectively combat the ever increasing and evolving deceptive activities in social medi
Anterior Hippocampus and Goal-Directed Spatial Decision Making
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115487.pdf (publisher's version ) (Open Access
Effect of Na doping on flux pinning of YBa1.9Na0.1Cu3O7-d
We have prepared Na-doped YBa2Cu3Oy (YBa1.9Na0.1Cu3Oy +40mol%Y211) (YBNCO)
and Na-free YBa2Cu3Oy (YBCO) samples by the Melt-Textured Growth (MTG) method
to study the effect of doped Na ion on flux pinning. The ac susceptibility
curves (acs) as well as the hysteresis loops were measured for the samples.
Then the effective pinning energy (U(T,Hdc,J)), irreversibility line (Hirr(T))
and critical current density (jc(Hdc)) were determined, where T, Hdc and J are
temperature, dc magnetic field and current density, respectively. We found
that, with Na doping, the Hirr(T) line shifted to lower temperature while the
Jc(Hdc) and U(T,Hdc,J) became smaller. It indicates that the Na ions play a
negative role in the flux pinning of YBCO. The appearance of the second peak in
the Jc(Hdc) curves and the enhancement of anisotropy in YBNCO further support
this finding.Comment: 7 pages, 7figures. Submited to Physica.
Numerical Simulation of Sediment Transport and Morphological Change of Upstream and Downstream Reach of Chi-Chi Weir
Hepatitis B virus subgenotype C2 is the most prevalent subgenotype in northeast China
AbstractThe geographical distribution of hepatitis B virus (HBV) subgenotypes and their clinical implications in patients with acute and chronic hepatitis B in the Heilung-kiang province of northeast China were investigated. Nested PCR and multiplex PCR were performed with genotype-specific primers and with subgenotype-specific primers to identify genotypes and subgenotypes from serum samples of 412 HBV infections including 69 with acute self-limited hepatitis (ASH) and 343 with chronic hepatitis (CH). A total of 361 samples were genotyped and 304 were further subgenotyped. The most common HBV genotype was C (93.63%, 338/361), with subgenotype group C2 (83.73%, 283/338) predominating. Genotype B was also found and subgenotype B2 predominated within this genotype. Out of 69 infected patients with ASH, 48 were identified as genotype C and all belonged to subgenotype C2. Of 343 infected patients with CH, 313 were genotyped and 256 were subgenotyped; amongst these, C2 (91.80%, 235/256), B2 (7.42%, 19/256) and mixed subgenotypes B2 and C2 (0.78%, 2/256) were found. In HBV subgenotype C2 infections, ASH had a higher ratio of women than CH patients. These results show that HBV subgenotypes C2 and B2 were found in Heilung-kiang province of northeast China. In ASH and CH groups, the distributions of subgenotypes were coincident with C2, the predominant subgenotype. Analysis of the association between subgenotype and the outcomes of HBV infection was inconclusive in our study
Chirality in odd- nucleus Nd in particle rotor model
A particle rotor model is developed which couples several valence protons and
neutrons to a rigid triaxial rotor core. It is applied to investigating the
chirality in odd- nucleus Nd with configuration for the first time in a fully quantal approach.
For the two chiral sister bands, the observed energies and the and
values for the in-band as well as interband transitions are reproduced
excellently. Root mean square values of the angular momentum components and
their probability distributions are used for discussing in detail the chiral
geometry of the aplanar rotation and its evolution with angular momentum.
Chirality is found to change from a soft chiral vibration to nearly static
chirality at spin and back to another type of chiral vibration at
higher spin.Comment: 16 pages, 5 figure
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