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Articles 1 - 30 of 181
Full-Text Articles in Physical Sciences and Mathematics
Personality And Programming, Amy B. Woszczynski, Tracy C. Guthrie, Sherri Shade
Personality And Programming, Amy B. Woszczynski, Tracy C. Guthrie, Sherri Shade
Sherri Shade
Information systems students continue to struggle to successfully complete computer programming classes. Learning how to program is difficult, and failure and attrition rates in college level programming classes remain at an unacceptably high rate. Since many IS students take a programming course as part of their program of study, IS educators should better understand why IS students tend to achieve low success rates in programming courses and what can be done to improve success rates. Little research to date has addressed potential reasons for student failure in programming principles courses. Many educators simply assume that high failure rates are acceptable …
A Call To Is Educators To Respond To The Voices Of Women In Information Security, Amy B. Woszczynski, Sherri Shade
A Call To Is Educators To Respond To The Voices Of Women In Information Security, Amy B. Woszczynski, Sherri Shade
Sherri Shade
Much prior research has examined the dearth of women in the IT industry. The purpose of this study is to examine the perceptions of women in IT within the context of information security and assurance. This paper describes results from a study of a relatively new career path to see if there are female-friendly opportunities that have not existed in previous IT career paths. Research methodology focuses on a qualitative analysis of in-depth interviews with women who are self-described information security professionals. A primary goal of the study is to understand the perceptions of women in information security and determine …
Solution Structure Of Domains Iva And V Of The Tau Subunit Of Escherichia Coli Dna Polymerase Iii And Interaction With The Alpha Subunit, Xun-Cheng Su, Slobodan Jergic, Max A Keniry, Nicholas E. Dixon, Gottfried Otting
Solution Structure Of Domains Iva And V Of The Tau Subunit Of Escherichia Coli Dna Polymerase Iii And Interaction With The Alpha Subunit, Xun-Cheng Su, Slobodan Jergic, Max A Keniry, Nicholas E. Dixon, Gottfried Otting
Professor Nick E Dixon
The solution structure of the C-terminal Domain V of the τ subunit of E. coli DNA polymerase III was determined by nuclear magnetic resonance (NMR) spectroscopy. The fold is unique to τ subunits. Amino acid sequence conservation is pronounced for hydrophobic residues that form the structural core of the protein, indicating that the fold is representative for τ subunits from a wide range of different bacteria. The interaction between the polymerase subunits τ and α was studied by NMR experiments where α was incubated with full-length C-terminal domain (τC16), and domains shortened at the C-terminus by 11 and 18 residues, …
Effect Of Protein Stabilization On Charge State Distribution In Positive- And Negative Ion Electrospray Ionization Mass Spectra, Stephen J. Watt, Margaret Sheil, Jennifer L. Beck, Pavel Prosselkov, Gottfried Otting, Nicholas E. Dixon
Effect Of Protein Stabilization On Charge State Distribution In Positive- And Negative Ion Electrospray Ionization Mass Spectra, Stephen J. Watt, Margaret Sheil, Jennifer L. Beck, Pavel Prosselkov, Gottfried Otting, Nicholas E. Dixon
Professor Nick E Dixon
Changes in protein conformation are thought to alter charge state distributions observed in electrospray ionization mass spectra (ESI-MS) of proteins. In most cases, this has been demonstrated by unfolding proteins through acidification of the solution. This methodology changes the properties of the solvent so that changes in the ESI-MS charge envelopes from conformational changes are difficult to separate from the effects of changing solvent on the ionization process. A novel strategy is presented enabling comparison of ESI mass spectra of a folded and partially unfolded protein of the same amino acid sequence subjected to the same experimental protocols and conditions. …
Architecture And Conservation Of The Bacterial Dna Replication Machinery, An Underexploited Drug Target, Andrew Robinson, Rebecca J. Causer, Nicholas E. Dixon
Architecture And Conservation Of The Bacterial Dna Replication Machinery, An Underexploited Drug Target, Andrew Robinson, Rebecca J. Causer, Nicholas E. Dixon
Professor Nick E Dixon
"New antibiotics with novel modes of action are required to combat the growing threat posed by multi-drug resistant bacteria. Over the last decade, genome sequencing and other high-throughput techniques have provided tremendous insight into the molecular processes underlying cellular functions in a wide range of bacterial species. We can now use these data to assess the degree of conservation of certain aspects of bacterial physiology, to help choose the best cellular targets for development of new broad-spectrum antibacterials. DNA replication is a conserved and essential process, and the large number of proteins that interact to replicate DNA in bacteria are …
Defining The Structural Basis Of Human Plasminogen Binding By Streptococcal Surface Enolase, Amanda J. Cork, Slobodan Jergic, Sven Hammerschmidt, Bostjan Kobe, Vijay Pancholi, Justin L.P. Benesch, Carol V, Robinson, Nicholas E. Dixon, J Andrew Aquilina, Mark J. Walker
Defining The Structural Basis Of Human Plasminogen Binding By Streptococcal Surface Enolase, Amanda J. Cork, Slobodan Jergic, Sven Hammerschmidt, Bostjan Kobe, Vijay Pancholi, Justin L.P. Benesch, Carol V, Robinson, Nicholas E. Dixon, J Andrew Aquilina, Mark J. Walker
Professor Nick E Dixon
The flesh-eating bacterium group A Streptococcus (GAS) binds and activates human plasminogen, promoting invasive disease. Streptococcal surface enolase (SEN), a glycolytic pathway enzyme, is an identified plasminogen receptor of GAS. Here we used mass spectrometry (MS) to confirm that GAS SEN is octameric, thereby validating in silico modeling based on the crystal structure of S. pneumoniae -enolase. Site-directed mutagenesis of surface-located lysine residues (SENK252+255A, SENK304A, SENK334A, SENK344E, SENK435L and SEN434-435) was used to examine their roles in maintaining structural integrity, enzymatic function and plasminogen binding. Structural integrity of the GAS SEN octamer was retained for all mutants except SENK344E, as …
Essential Biological Processes Of An Emerging Pathogen: Dna Replication, Transcription, And Cell Division In Acinetobacter Spp., Andrew Robinson, Anthony J. Brzoska, Kylie M. Turner, Ryan Withers, Elizabeth J. Harry, Peter J. Lewis, Nicholas E. Dixon
Essential Biological Processes Of An Emerging Pathogen: Dna Replication, Transcription, And Cell Division In Acinetobacter Spp., Andrew Robinson, Anthony J. Brzoska, Kylie M. Turner, Ryan Withers, Elizabeth J. Harry, Peter J. Lewis, Nicholas E. Dixon
Professor Nick E Dixon
Species of the bacterial genus Acinetobacter are becoming increasingly important as a source of hospital-acquired infections (31, 185, 204). Acinetobacter spp. are ubiquitous nonmotile gammaproteobacteria, typified by metabolic versatility and a capacity for natural transformation (172, 204). The species of most clinical relevance is A. baumannii; however, pathogenic strains of A. lwoffi and A. baylyi have also been described (38, 185, 215).
Incorporation Of Chlorinated Analogues Of Aliphatic Amino Acids During Cell-Free Protein Synthesis, Dannon J. Stigers, Zachary I. Watts, James E. Hennessy, Hye-Kyung Kim, Romeo Martini, Matthew C. Taylor, Kiyoshi Ozawa, Jeffrey W. Keillor, Nicholas E. Dixon, Christopher J. Easton
Incorporation Of Chlorinated Analogues Of Aliphatic Amino Acids During Cell-Free Protein Synthesis, Dannon J. Stigers, Zachary I. Watts, James E. Hennessy, Hye-Kyung Kim, Romeo Martini, Matthew C. Taylor, Kiyoshi Ozawa, Jeffrey W. Keillor, Nicholas E. Dixon, Christopher J. Easton
Professor Nick E Dixon
3-Chloro-Abu and 4-chloro-Nva are biosynthetically incorporated into E. coli peptidyl-Pro cis-trans isomerase B, as substitutes for Val and Leu, respectively. The extent of incorporation is up to 90%, and substituted protein is catalytically active. By contrast, 4-chloro-Val is not an effective replacement for Ile.
Nanometer-Scale Distance Measurements In Proteins Using Gd3+ Spin Labeling, Alexey Potapov, Hiromasa Yagi, Thomas Huber, Slobodan Jergic, Nicholas E. Dixon, Gottfried Otting, Daniella Goldfarb
Nanometer-Scale Distance Measurements In Proteins Using Gd3+ Spin Labeling, Alexey Potapov, Hiromasa Yagi, Thomas Huber, Slobodan Jergic, Nicholas E. Dixon, Gottfried Otting, Daniella Goldfarb
Professor Nick E Dixon
Methods for measuring nanometer-scale distances between specific sites in proteins are essential for analysis of their structure and function. In this work we introduce Gd3+ spin labeling for nanometer-range distance measurements in proteins by high-field pulse electron paramagnetic resonance (EPR). To evaluate the performance of such measurements, we carried out four-pulse double-electron electron resonance (DEER) measurements on two proteins, p75ICD and τC14, labeled at strategically selected sites with either two nitroxides or two Gd3+ spin labels. In analogy to conventional site-directed spin labeling using nitroxides, Gd3+ tags that are derivatives of dipicolinic acid were covalently attached to cysteine thiol groups. …
Proteomic Dissection Of Dna Polymerization, Jennifer L. Beck, Thitima Urathamakul, Stephen James Watt, Margaret Sheil, Patrick M. Schaeffer, Nicholas E. Dixon
Proteomic Dissection Of Dna Polymerization, Jennifer L. Beck, Thitima Urathamakul, Stephen James Watt, Margaret Sheil, Patrick M. Schaeffer, Nicholas E. Dixon
Professor Nick E Dixon
DNA polymerases replicate the genome by associating with a range of other proteins that enable rapid, high-fidelity copying of DNA. This complex of proteins and nucleic acids is called the replisome. Proteins of the replisome must interact with other networks of proteins, such as those involved in DNA repair. Many of the proteins involved in DNA polymerisation and the accessory proteins are known, but the array of proteins they interact with, and the spatial and temporal arrangement of these interactions is a current research topic. Mass spectrometry is a technique that can be used to identify the sites of these …
Helicase-Binding To Dnai Exposes A Cryptic Dna-Binding Site During Helicase Loading In Bacillus Subtilis, Charikleia Ioannou, Patrick M. Schaeffer, Nicholas E. Dixon, Panos Soultanas
Helicase-Binding To Dnai Exposes A Cryptic Dna-Binding Site During Helicase Loading In Bacillus Subtilis, Charikleia Ioannou, Patrick M. Schaeffer, Nicholas E. Dixon, Panos Soultanas
Professor Nick E Dixon
The Bacillus subtilis DnaI, DnaB and DnaD proteins load the replicative ring helicase DnaC onto DNA during priming of DNA replication. Here we show that DnaI consists of a C-terminal domain (Cd) with ATPase and DNA-binding activities and an N-terminal domain (Nd) that interacts with the replicative ring helicase. A Zn21-binding module mediates the interaction with the helicase and C67, C70 and H84 are involved in the coordination of the Zn21. DnaI binds ATP and exhibits ATPase activity that is not stimulated by ssDNA, because the DNAbinding site on Cd is masked by Nd. The ATPase activity resides on the …
Ultrasensitive Detection Of Antibodies Using A New Tus-Ter-Lock Immunopcr System, Isabelle Morin, Nicholas E. Dixon, Patrick M. Schaeffer
Ultrasensitive Detection Of Antibodies Using A New Tus-Ter-Lock Immunopcr System, Isabelle Morin, Nicholas E. Dixon, Patrick M. Schaeffer
Professor Nick E Dixon
A system consisting of a protein LG coated surface for the capture of mammalian antibodies (target), and an antigen fused to Tus and stoichiometrically linked to a DNA template via the Tus-Ter-lock sequence allowed the ultrasensitive detection of 5.5 attomol of target by real-time immunoPCR in complex media. © The Royal Society of Chemistry 2010.
The Unstructured C-Terminus Of The Tau Subunit Of Escherichia Coli Dna Polymerase Iii Holoenzyme Is The Site Of Interaction With The Alpha Subunit, Slobodan Jergic, Kiyoshi Ozawa, Neal K. Williams, Xun-Cheng Su, Daniel D. Scott, Samir M. Hamdan, Jeffrey A. Crowther, Gottfried Otting, Nicholas E. Dixon
The Unstructured C-Terminus Of The Tau Subunit Of Escherichia Coli Dna Polymerase Iii Holoenzyme Is The Site Of Interaction With The Alpha Subunit, Slobodan Jergic, Kiyoshi Ozawa, Neal K. Williams, Xun-Cheng Su, Daniel D. Scott, Samir M. Hamdan, Jeffrey A. Crowther, Gottfried Otting, Nicholas E. Dixon
Professor Nick E Dixon
The τ subunit of Escherichia coli DNA polymerase III holoenzyme interacts with the α subunit through its C-terminal Domain V, τC16. We show that the extreme C-terminal region of τC16 constitutes the site of interaction with α. The τC16 domain, but not a derivative of it with a C-terminal deletion of seven residues (τC16Δ7), forms an isolable complex with α. Surface plasmon resonance measurements were used to determine the dissociation constant (KD) of the α−τC16 complex to be ∼260 pM. Competition with immobilized τC16 by τC16 derivatives for binding to α gave values of KD of 7 μM for the …
High-Yield Cell-Free Protein Synthesis For Site-Specific Incorporation Of Unnatural Amino Acids At Two Sites, Kiyoshi Ozawa, Karin V. Loscha, Kekini V. Kuppan, Choy Theng Loh, Nicholas E. Dixon, Gottfried Otting
High-Yield Cell-Free Protein Synthesis For Site-Specific Incorporation Of Unnatural Amino Acids At Two Sites, Kiyoshi Ozawa, Karin V. Loscha, Kekini V. Kuppan, Choy Theng Loh, Nicholas E. Dixon, Gottfried Otting
Professor Nick E Dixon
Using aminoacyl-tRNA synthetase/suppressor tRNA pairs derived from Methanocaldococcus jannaschii, an Escherichia coli cell-free protein production system affords proteins with site-specifically incorporated unnatural amino acids (UAAs) in high yields through the use of optimized amber suppressor tRNACUA opt and optimization of reagent concentrations. The efficiency of the cell-free system allows the incorporation of trifluoromethyl-phenylalanine using a polyspecific synthetase evolved previously for p-cyanophenylalanine, and the incorporation of UAAs at two different sites of the same protein without any re-engineering of the E. coli cells used to make the cell-free extract.
Site-Specific Covalent Attachment Of Dna To Proteins Using A Photoactivatable Tus-Ter Complex, Dahdah B. Dahdah, Isabelle Morin, Morgane Moreau, Nicholas E. Dixon, Patrick M. Schaeffer
Site-Specific Covalent Attachment Of Dna To Proteins Using A Photoactivatable Tus-Ter Complex, Dahdah B. Dahdah, Isabelle Morin, Morgane Moreau, Nicholas E. Dixon, Patrick M. Schaeffer
Professor Nick E Dixon
Investigations into the photocrosslinking kinetics of the protein Tus with various bromodeoxyuridine-substituted Ter DNA variants highlight the potential use of this complex as a photoactivatable connector between proteins of interest and specific DNA sequences.
Synthesis And Applications Of Covalent Protein-Dna Conjugates, Patrick M. Schaeffer, Nicholas E. Dixon
Synthesis And Applications Of Covalent Protein-Dna Conjugates, Patrick M. Schaeffer, Nicholas E. Dixon
Professor Nick E Dixon
Synthetic protein-DNA conjugates are valuable tools with applications in fields including nanobiotechnology, bioanalytical chemistry, and molecular diagnostics, and various synthetic methods for their production have been developed during the past three decades. The present article reviews current methodologies for the synthesis of covalent protein-DNA conjugates with particular focus on the regiospecificity and stoichiometry of these reactions.
The Proofreading Exonuclease Subunit E Of Escherichia Coli Dna Polymerase Iii Is Tethered To The Polymerase Subunit A Via A Flexible Linker, Kiyoshi Ozawa, Slobodan Jergic, Ah-Young Park, Nicholas E. Dixon, Gottfried Otting
The Proofreading Exonuclease Subunit E Of Escherichia Coli Dna Polymerase Iii Is Tethered To The Polymerase Subunit A Via A Flexible Linker, Kiyoshi Ozawa, Slobodan Jergic, Ah-Young Park, Nicholas E. Dixon, Gottfried Otting
Professor Nick E Dixon
Escherichia coli DNA polymerase III holoenzyme is composed of 10 different subunits linked by noncovalent interactions. The polymerase activity resides in the α-subunit. The ε-subunit, which contains the proofreading exonuclease site within its N-terminal 185 residues, binds to α via a segment of 57 additional C-terminal residues, and also to θ, whose function is less well defined. The present study shows that θ greatly enhances the solubility of ε during cell-free synthesis. In addition, synthesis of ε in the presence of θ and α resulted in a soluble ternary complex that could readily be purified and analyzed by NMR spectroscopy. …
A Novel Zinc-Binding Fold In The Helicase Interaction Domain Of The Bacillus Subtilis Dnal Helicase Loader, Karin V. Loscha, Kristaps Jaudzems, Charikleia Ioannou, Xun-Cheng Su, Flynn R. Hill, Gottfried Otting, Nicholas E. Dixon, Edvards Liepinsh
A Novel Zinc-Binding Fold In The Helicase Interaction Domain Of The Bacillus Subtilis Dnal Helicase Loader, Karin V. Loscha, Kristaps Jaudzems, Charikleia Ioannou, Xun-Cheng Su, Flynn R. Hill, Gottfried Otting, Nicholas E. Dixon, Edvards Liepinsh
Professor Nick E Dixon
The helicase loader protein DnaI (the Bacillus subtilis homologue of Escherichia coli DnaC) is required to load the hexameric helicase DnaC (the B. subtilis homologue of E. coli DnaB) onto DNA at the start of replication. While the C-terminal domain of DnaI belongs to the structurally well-characterized AAA+ family of ATPases, the structure of the N-terminal domain, DnaI-N, has no homology to a known structure. Three-dimensional structure determination by nuclear magnetic resonance (NMR) spectroscopy shows that DnaI presents a novel fold containing a structurally important zinc ion. Surface plasmon resonance experiments indicate that DnaI-N is largely responsible for binding of …
Human Tracking Technology In Mutual Legal Assistance And Police Inter-State Cooperation In International Crimes, Katina Michael, G. L. Rose
Human Tracking Technology In Mutual Legal Assistance And Police Inter-State Cooperation In International Crimes, Katina Michael, G. L. Rose
Professor Gregory Rose
The objective of this paper is to explore the role of human tracking technology, primarily the use of global positioning systems (GPS) in locating individuals for the purposes of mutual legal assistance (MLA), and providing location intelligence for use in inter-state police cooperation within the context of transnational crime. GPS allows for the 24/7 continuous real-time tracking of an individual, and is considered manifold more powerful than the traditional visual surveillance often exercised by the police. As the use of GPS for human tracking grows in the law enforcement sector, federal and state laws in many countries are to a …
Design And Estimation For Split Questionnaire Surveys, James O. Chipperfield, David G. Steel
Design And Estimation For Split Questionnaire Surveys, James O. Chipperfield, David G. Steel
Professor David Steel
When sampling from a finite population to estimate the means or totals of K population characteristics of interest, survey designs typically impose the constraint that information on all K characteristics (or data items) is collected from all units in the sample. Relaxing this constraint means that information on a subset of the K data items may be collected from any given unit in the sample. Such a design, called a split questionnaire design (SQD), has three advantages over the typical design: increased efficiency with which design objectives can be met, by allowing the number of sample units from which information …
Conditional And Unconditional Models In Model-Assisted Estimation Of Finite Population Totals, David Steel, Robert Clark
Conditional And Unconditional Models In Model-Assisted Estimation Of Finite Population Totals, David Steel, Robert Clark
Professor David Steel
The well known Godambe-Joshi lower bound for the anticipated variance of design unbiased estimators of population totals treats the auxiliary variables as constants. We extend the result to models where these variables are random and show that the generalized difference estimator using the expected values conditional on all auxiliary values is optimal. This has several implications including the fact that collecting multiple survey variables does not reduce the lower bound.
Scales, Levels And Processes: Studying Spatial Patterns Of British Census Variables, David Manley, Robin Flowerdew, David Steel
Scales, Levels And Processes: Studying Spatial Patterns Of British Census Variables, David Manley, Robin Flowerdew, David Steel
Professor David Steel
No abstract provided.
Measuring And Analysing Homogeneity Of Geographical Areas For A Categorical Variable, David Steel, Mark Tranmer
Measuring And Analysing Homogeneity Of Geographical Areas For A Categorical Variable, David Steel, Mark Tranmer
Professor David Steel
Many Variables have within group homogeneity (similarity of values for the individual units that comprise the groups). Measures of within group homogeneity are useful for the sample design and statistical analysis of datasets for populations that contain groups, such as individuals in geographical areas. Homogeneity measures can easily be defined for continuous or dichotomous variables. Here we propose a homogeneity measure for a multi-category variable and show how this measure can be calculated without access to individual level data. We apply the measure to data from the UK census and show how this measure can be related to the homogeneity …
Orbital Structure Of Fetio3 Ilmenite Investigated With Polarization-Dependent X-Ray Absorption Spectroscopy And Band Structure Calculations, S W. Chen, M J. Huang, P A. Lin, H T. Jeng, J M. Lee, S C. Haw, S A. Chen, H J. Lin, K T. Lu, Dapeng Chen, S X. Dou, X L. Wang, J M. Chen
Orbital Structure Of Fetio3 Ilmenite Investigated With Polarization-Dependent X-Ray Absorption Spectroscopy And Band Structure Calculations, S W. Chen, M J. Huang, P A. Lin, H T. Jeng, J M. Lee, S C. Haw, S A. Chen, H J. Lin, K T. Lu, Dapeng Chen, S X. Dou, X L. Wang, J M. Chen
Shi Xue Dou
We explored the orbital structure of FeTiO3 with polarization-dependent x-ray absorption spectra complemented with electronic structure calculations. The electronic structure, near the bottom of conduction band, is composed of O 2p and Ti 3d orbitals. Ti 3d/4p hybridization dominantly lies on the ab plane. The highly delocalized Ti 4p orbital might hybridize with O 2p orbital and even extend to the next-neighbor Fe atom whereby establishing a linear orbital combination of Ti-O-Fe. A clear picture of the orbital construction in FeTiO3 will help to elucidate the paths of pressure-induced charge transfer and other physical or magnetic characteristics.
Magnetic Properties Of Bi2femno6: A Multiferroic Material With Double-Perovskite Structure, Yi Du, Zhenxiang Cheng, S X. Dou, Xiaolin Wang, Hua Zhao, Hideo Kimura
Magnetic Properties Of Bi2femno6: A Multiferroic Material With Double-Perovskite Structure, Yi Du, Zhenxiang Cheng, S X. Dou, Xiaolin Wang, Hua Zhao, Hideo Kimura
Shi Xue Dou
Single phase Bi2FeMnO6 was synthesized on Si substrates by an electrospray method. Three peaks were observed in the temperature dependence of magnetization curve, which is attributed to the inhomogeneous distribution of Fe3+ and Mn3+. The observed magnetic peaks at 150 K, 260 K, and 440 K correspond to orderings of the ferrimagnetic Fe–O–Mn, and antiferromagnetic Mn–O–Mn and Fe–O–Fe, respectively. Heat capacity measurements were carried out to confirm these magnetic transitions. The Debye temperature of Bi2FeMnO6 is 339 K, calculated from Debye–Einstein fitting.
The Effects Of Annealing Temperature On The In-Field Jc And Surface Pinning In Silicone Oil Doped Mgb2 Bulks And Wires, M S. Hossain, A Motaman, O Cicek, H Agil, E Ertekin, A Gencer, Xiaolin Wang, S X. Dou
The Effects Of Annealing Temperature On The In-Field Jc And Surface Pinning In Silicone Oil Doped Mgb2 Bulks And Wires, M S. Hossain, A Motaman, O Cicek, H Agil, E Ertekin, A Gencer, Xiaolin Wang, S X. Dou
Shi Xue Dou
No abstract provided.
Apparent Negative Mobility Of Vortex Matter Due To Inhomogeneous Pinning, X B Xu, H Fangohr, Shichao Ding, M Gu, T.B Tang, Z Han, Dongqi Shi, S X. Dou
Apparent Negative Mobility Of Vortex Matter Due To Inhomogeneous Pinning, X B Xu, H Fangohr, Shichao Ding, M Gu, T.B Tang, Z Han, Dongqi Shi, S X. Dou
Shi Xue Dou
We investigate the transport of vortices in superconductors with inhomogeneous pinning under a driving force. The inhomogeneity of pinning is simplified as strong-weak pinning regions. It is demonstrated that the interactions between the vortices captured by strong pinning potentials and the vortices in the weak pinning region cause absolute negative motion (ANM) of vortices: The vortices which are climbing toward the high barriers induced by the strong pinning with the help of driving force move toward the opposite direction of the force and back to their equilibrium positions in the weak pinning region as the force decreases or is withdrawn. …
Inhomogeneities In Yba 2cu 3o 7 Thin Films With Reduced Thickness, O V. Shcherbakova, A V. Pan, S K. Gorman, S A. Fedoseev, I A. Golovchanskiy, S. X. Dou
Inhomogeneities In Yba 2cu 3o 7 Thin Films With Reduced Thickness, O V. Shcherbakova, A V. Pan, S K. Gorman, S A. Fedoseev, I A. Golovchanskiy, S. X. Dou
Shi Xue Dou
Morphology and physical properties of mono- (YBa2Cu3O7) and multilayered (YBa2Cu3O7/SmBa2Cu3O7/ YBa2Cu3O7) superconducting thin films with thickness ranging from 90 nm to 28 nm have been investigated. For both types of samples, the superconducting properties degraded with reduction of film thickness. Structural and electromagnetic properties were visualized through scanning electron microscopy and magneto-optical imaging, respectively, and revealed high level of inhomogeneity for thinner (<58 >nm) samples. However, samples with thickness above 58 nm showed enhanced homogeneity, which …
Flux Distribution In Fe-Based Superconducting Materials By Magneto-Optical Imaging, Zhi Wei Lin, Jian Guo Zhu, You Guang Guo, Xiaolin Wang, S X. Dou, Tom H. Johansen, Xun Shi, K Y. Choi
Flux Distribution In Fe-Based Superconducting Materials By Magneto-Optical Imaging, Zhi Wei Lin, Jian Guo Zhu, You Guang Guo, Xiaolin Wang, S X. Dou, Tom H. Johansen, Xun Shi, K Y. Choi
Shi Xue Dou
"This paper presents the magnetic flux distributions in Fe-based superconducting materials including single crystal of Ba(Fe1.9Ni0.1)As2 and Ba(Fe1.8Co0.2)As2, as well as polycrystalline SmFeO0.75F0.2As by means of magneto-optical imaging (MOI) technique. The single crystals were grown out of FeAs flux while polycrystalline sample was grown by hot-press. A MOI film with in-plan magnetization was used to visualize flux distributions at the sample surface. A series of magneto-optical images was taken when the samples were zero-field cooled and field cooled. The flux behavior, including penetration into and expelling from the samples, as well as pinning properties were studied. When external fields increase, …
Anisotropic And Excellent Magnetocaloric Properties Of La 0.7ca0.3mno3 Single Crystal With Anomalous Magnetization, J.C Debnath, Rong Zeng, Jung Ho Kim, Dapeng Chen, S X. Dou
Anisotropic And Excellent Magnetocaloric Properties Of La 0.7ca0.3mno3 Single Crystal With Anomalous Magnetization, J.C Debnath, Rong Zeng, Jung Ho Kim, Dapeng Chen, S X. Dou
Shi Xue Dou
Magnetic properties and the magnetocaloric effect (MCE) have been investigated in La0.7Ca0.3MnO3 single crystal with applied field along both the ab-plane and the c-direction. Due to the magnetocrystalline anisotropy, the crystal exhibits anisotropy in the MCE. Upon application of a 5 T field, the magnetic entropy changes (SM), reaching values of 7.668 J/(kg K) and 6.412 J/(kg K) for both the ab-plane and the c-direction, respectively. A magnetic entropy change of 3.3 J/(kg K) was achieved for a magnetic field change of 1.5 T at the Curie temperature, TC = 245 K. Due to the absence of grains in the …