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Full-Text Articles in Physical Sciences and Mathematics
Room Temperature Giant And Linear Magnetoresistance In Topological Insulator Bi2te3 Nanosheets, Xiaolin Wang, Yi Du, S X. Dou, Chao Zang
Room Temperature Giant And Linear Magnetoresistance In Topological Insulator Bi2te3 Nanosheets, Xiaolin Wang, Yi Du, S X. Dou, Chao Zang
Shi Xue Dou
"Topological insulators, a new class of condensed matter having bulk insulating states and gapless metallic surface states, have demonstrated fascinating quantum effects. However, the potential practical applications of the topological insulators are still under exploration worldwide. We demonstrate that nanosheets of a Bi2Te3 topological insulator several quintuple layers thick display giant and linear magnetoresistance. The giant and linear magnetoresistance achieved is as high as over 600% at room temperature, with a trend towards further increase at higher temperatures, as well as being weakly temperature-dependent and linear with the field, without any sign of saturation at measured fields up to 13 …
Enhancement Of Transition Temperature In Fexse0.5te0.5 Film Via Iron Vacancies, J C. Zhuang, Wai K. Yeoh, Xiangyuan Cui, Jung Ho Kim, Dongqi Shi, Z X. Shi, S P. Ringer, Xiaolin Wang, S X. Dou
Enhancement Of Transition Temperature In Fexse0.5te0.5 Film Via Iron Vacancies, J C. Zhuang, Wai K. Yeoh, Xiangyuan Cui, Jung Ho Kim, Dongqi Shi, Z X. Shi, S P. Ringer, Xiaolin Wang, S X. Dou
Shi Xue Dou
The effects of iron deficiency in Fe x Se0.5Te0.5 thin films (0.8 ≤ x ≤ 1) on superconductivity and electronic properties have been studied. A significant enhancement of the superconducting transition temperature (TC ) up to 21 K was observed in the most Fe deficient film (x = 0.8). Based on the observed and simulated structural variation results, there is a high possibility that Fe vacancies can be formed in the Fe x Se0.5Te0.5 films. The enhancement of TC shows a strong relationship with the lattice strain effect induced by Fe vacancies. Importantly, the presence of Fe vacancies alters the …
Ultra-High Performance, High-Temperature Superconducting Wires Via Cost-Effective, Scalable, Co-Evaporation Process, Ho-Sup Kim, Sang-Soo Oh, Hong-Soo Ha, Dojun Youm, Seung-Hyun Moon, Jung Ho Kim, S X. Dou, Yoon-Uk Heo, Sung-Hun Wee, Amit Goyal
Ultra-High Performance, High-Temperature Superconducting Wires Via Cost-Effective, Scalable, Co-Evaporation Process, Ho-Sup Kim, Sang-Soo Oh, Hong-Soo Ha, Dojun Youm, Seung-Hyun Moon, Jung Ho Kim, S X. Dou, Yoon-Uk Heo, Sung-Hun Wee, Amit Goyal
Shi Xue Dou
Long-length, high-temperature superconducting (HTS) wires capable of carrying high critical current, Ic, are required for a wide range of applications. Here, we report extremely high performance HTS wires based on 5 μm thick SmBa2Cu3O7 − δ (SmBCO) single layer films on textured metallic templates. SmBCO layer wires over 20 meters long were deposited by a cost-effective, scalable co-evaporation process using a batch-type drum in a dual chamber. All deposition parameters influencing the composition, phase, and texture of the films were optimized via a unique combinatorial method that is broadly applicable for co-evaporation of other promising complex materials containing several cations. …
Partial Molecular Volumes Of Lipids And Cholesterol., Alexander Greenwood, Stephanie Tristram-Nagle, John Nagle
Partial Molecular Volumes Of Lipids And Cholesterol., Alexander Greenwood, Stephanie Tristram-Nagle, John Nagle
Prof. Stephanie Tristram-Nagle Ph.D.
Volumetric measurements are reported for fully hydrated lipid/cholesterol bilayer mixtures using the neutral flotation method. Apparent specific volume data were obtained with the lipids DOPC, POPC and DMPC at T=30 degrees Celsius, DPPC at 50 degrees Celsius, and brain sphingomyelin (BSM) at 45 and 24 degrees Celsius for mole fractions of cholesterol x from 0 to 0.5. Unlike previous cholesterol mixture studies, we converted our raw data to partial molecular volume V(L) of the lipid and V(C) of the cholesterol. The partial molecular volumes were constant for POPC and DOPC as x was varied, but had sharp breaks for the …
Structure Of Lipid Bilayers, John Nagle, Stephanie Tristram-Nagle
Structure Of Lipid Bilayers, John Nagle, Stephanie Tristram-Nagle
Prof. Stephanie Tristram-Nagle Ph.D.
The quantitative experimental uncertainty in the structure of fully hydrated, biologically relevant, fluid (L(alpha)) phase lipid bilayers has been too large to provide a firm base for applications or for comparison with simulations. Many structural methods are reviewed including modern liquid crystallography of lipid bilayers that deals with the fully developed undulation fluctuations that occur in the L(alpha) phase. These fluctuations degrade the higher order diffraction data in a way that, if unrecognized, leads to erroneous conclusions regarding bilayer structure. Diffraction measurements at high instrumental resolution provide a measure of these fluctuations. In addition to providing better structural determination, this …
Molecular Structures Of Fluid Phase Phosphatidylglycerol Bilayers As Determined By Small Angle Neutron And X-Ray Scattering., Jianjun Pan, Frederick Heberle, Stephanie Tristram-Nagle, Michelle Szymanski, Mary Koepfinger, John Katsaras, Norbert Kucerka
Molecular Structures Of Fluid Phase Phosphatidylglycerol Bilayers As Determined By Small Angle Neutron And X-Ray Scattering., Jianjun Pan, Frederick Heberle, Stephanie Tristram-Nagle, Michelle Szymanski, Mary Koepfinger, John Katsaras, Norbert Kucerka
Prof. Stephanie Tristram-Nagle Ph.D.
We have determined the molecular structures of commonly used phosphatidylglycerols (PGs) in the commonly accepted biologically relevant fluid phase. This was done by simultaneously analyzing small angle neutron and X-ray scattering data, with the constraint of measured lipid volumes. We report the temperature dependence of bilayer parameters obtained using the one-dimensional scattering density profile model - which was derived from molecular dynamics simulations - including the area per lipid, the overall bilayer thickness, as well as other intrabilayer parameters (e.g., hydrocarbon thickness). Lipid areas are found to be larger than their phosphatidylcholine (PC) counterparts, a result likely due to repulsive …
Orientation Of Tie-Lines In The Phase Diagram Of Dopc/Dppc/Cholesterol Model Biomembranes., Pradeep Uppamoochikkal, Stephanie Tristram-Nagle, John Nagle
Orientation Of Tie-Lines In The Phase Diagram Of Dopc/Dppc/Cholesterol Model Biomembranes., Pradeep Uppamoochikkal, Stephanie Tristram-Nagle, John Nagle
Prof. Stephanie Tristram-Nagle Ph.D.
We report the direction of tie-lines of coexisting phases in a ternary diagram of DOPC/DPPC/cholesterol lipid bilayers, which has been a system of interest in the discussion of biological rafts. For coexisting Ld and Lo phases, we find that the orientation angle α of the tie-lines increases as the cholesterol concentration increases and it also increases as temperature increases from T = 15 °C to T = 30 °C. Results at lower cholesterol concentrations support the existence of a different two-phase coexistence region of Ld and So phases and the existence of a three-phase region separating the two two-phase regions. …
Volumetric Stability Of Lipid Bilayers., Kelsey Hallinen, Stephanie Tristram-Nagle, John Nagle
Volumetric Stability Of Lipid Bilayers., Kelsey Hallinen, Stephanie Tristram-Nagle, John Nagle
Prof. Stephanie Tristram-Nagle Ph.D.
In agreement with recent reports, a commercial densimeter has yielded a gradual decrease in lipid molecular volume of DPPC multilamellar vesicle dispersions in the gel phase upon repeated thermal cycling between 10 °C and 50 °C. The considerable size of this decrease would have significant implications for the physical chemistry of biomembranes. In contrast, neutral buoyancy measurements performed with similar thermal cycling indicate no gradual change in lipid volume in the gel phase at 20 °C. Remixing the lipid in the densimeter shows that the apparent volume decrease is an artifact. We conclude that gel phase DPPC bilayers exist in …
Rational Design Of P-Type Thermoelectric Pbte: Temperature Dependent Sodium Solubility, Sima Aminorroaya-Yamini, Teruyuki Ikeda, Aaron Lalonde, Yanzhong Pei, S X. Dou, G. Jeffrey Snyder
Rational Design Of P-Type Thermoelectric Pbte: Temperature Dependent Sodium Solubility, Sima Aminorroaya-Yamini, Teruyuki Ikeda, Aaron Lalonde, Yanzhong Pei, S X. Dou, G. Jeffrey Snyder
Shi Xue Dou
We develop a solid understanding of the termperature-dependent solubility of sodium p-type PbTe, the most efficient thermoelectric material. The maximum solubility of socium telluride (NaTe) in PbTe is measured to be 1.4+0.3 at percent and the heat of solution is evaluated and that addresses fundamental issues regarding the formation of nano-precipitates.