Abstract
Superconductivity in the cuprates is found to be intertwined with charge and spin density waves. Determining the interactions between the different types of order is crucial for ...understanding these important materials. Here, we elucidate the role of the charge density wave (CDW) in the prototypical cuprate La
1.885
Sr
0.115
CuO
4
, by studying the effects of large magnetic fields (
H
) up to 24 Tesla. At low temperatures (
T
), the observed CDW peaks reveal two distinct regions in the material: a majority phase with short-range CDW coexisting with superconductivity, and a minority phase with longer-range CDW coexisting with static spin density wave (SDW). With increasing magnetic field, the CDW first grows smoothly in a manner similar to the SDW. However, at high fields we discover a sudden increase in the CDW amplitude upon entering the vortex-liquid state. Our results signify strong coupling of the CDW to mobile superconducting vortices and link enhanced CDW amplitude with local superconducting pairing across the
H
−
T
phase diagram.
Choosing Two-Dimensional (2-D) layered semiconductor material MoS2 as the insulator, FeSiAl/MoS2 composites were synthesized by mixing MoS2 and aerosolized FeSiAl in a certain mass ratio. The ...structure, morphology and magnetic properties of FeSiAl/MoS2 composites were measured by XRD, SEM, XPS, VSM and B-H analyzer. The SEM results show that high-speed ball milling breaks the binding of weak Van der Waals force between MoS2 layers, and nano-thick MoS2 micron flakes wrapped on the FeSiAl spherical surface. The results of magnetic properties show that not only the FeSiAl/MoS2 composite achieves a higher magnetic permeability due to the thin MoS2 flakes clinging to the FeSiAl particle surface, but also the eddy current between the metallic particles is blocked, resulting in a great reduction of eddy current loss. The permeability results show that the relaxation frequency of FeSiAl/MoS2 composites exceeds 1 MHz, which is suitable for application at high frequency. The magnetic loss of FeSiAl/1 wt%MoS2 composite reaches 454kWm−3 under the condition of f= 0.1 MHz and B= 0.1 T, which is about three quarters of that of FeSiAl soft magnetic composites for commercial application.
•The two-dimensional layered semiconductor material MoS2 is selected as the insulator.•The magnetic loss of FeSiAl/1 wt% MoS2 composites is greatly reduced.•FeSiAl/1 wt% MoS2 Composite has high permeability and low hysteresis loss.•MoS2 can be stripped into thin slices by high-speed ball milling.
We report the timing results for PSR J2234+0611, a 3.6 ms pulsar in a 32 day, eccentric (e = 0.13) orbit with a helium white dwarf. The precise timing and eccentric nature of the orbit allow ...measurements of an unusual number of parameters: (a) a precise proper motion of 27.10(3) mas yr−1 and a parallax of 1.05(4) mas resulting in a pulsar distance of 0.95(4) kpc; enabling an estimate of the transverse velocity, 123(5) km s−1. Together with previously published spectroscopic measurements of the systemic radial velocity, this allows a 3D determination of the system's velocity; (b) precise measurements of the rate of advance of periastron yields a total system mass of M ; (c) a Shapiro delay measurement, h3 = 82 14 ns, despite the orbital inclination not being near 90°; combined with the measurement of the total mass yields a pulsar mass of and a companion mass of (d) we measure precisely the secular variation of the projected semimajor axis and detect a significant annual orbital parallax; together these allow a determination of the 3D orbital geometry of the system, including an unambiguous orbital inclination ( ) and a position angle for the line of nodes ( ). We discuss the component masses to investigate the hypotheses previously advanced to explain the origin of eccentric MSPs. The unprecedented determination of the 3D position, motion, and orbital orientation of the system, plus the precise pulsar and WD masses and the latter's optical detection make this system a unique test of our understanding of white dwarfs and their atmospheres.
Immunity acquired from infection or vaccination protects humans from symptomatic hepatitis E. However, whether the risk of hepatitis E virus (HEV) infection is reduced by the immunity remains ...unknown. To understand this issue, a cohort with 12 409 participants randomized to receive the hepatitis E vaccine Hecolin® or placebo were serologically followed up for 2 years after vaccination. About half (47%) of participants were initially seropositive. A total of 139 infection episodes, evidenced by four-fold or greater rise of anti-HEV level or positive seroconversion, occurred in participants who received three doses of treatment. Risk of infection was highest among the baseline seronegative placebo group participants (2.04%). Pre-existing immunity and vaccine-induced immunity lower the risk significantly, to 0.52% and 0.30%, respectively. In conclusion, both vaccine-induced and naturally acquired immunity can effectively protect against HEV infection.
High ionic conductivity, varying from 0.01 to 1
S
cm
−1 between 300 and 700
°C, has been achieved for the hybrid and nano-ceria-composite electrolyte materials, demonstrating a successful application ...for advanced low temperature solid oxide fuel cells (LTSOFCs). The LTSOFCs were constructed based on these new materials. The performance of 0.15–0.25
W
cm
−2 was obtained in temperature region of 320–400
°C for the ceria-carbonate composite electrolyte, and of 0.35–0.66
W
cm
−2 in temperature region of 500–600
°C for the ceria-lanthanum oxide composites. The cell could even function at as low as 200
°C. The cell has also undergone a life test for several months. A two-cell stack was studied, showing expected performance successfully.
The excellent LTSOFC performance is resulted from both functional electrolyte and electrode materials. The electrolytes are two phase composite materials based on the oxygen ion and proton conducting phases, or two rare-earth oxides. The electrodes used were based on the same composite material system having excellent compatibility with the electrolyte. They are highly catalytic and conductive thus creating the excellent performances at low temperatures. These innovative LT materials and LTSOFC technologies would open the door for wide applications, not only for stationary but also for mobile power sources.
Abstract
Fossil CO
2
emissions in 2021 grew an estimated 4.2% (3.5%–4.8%) to 36.2 billion metric tons compared with 2020, pushing global emissions back close to 2019 levels (36.7 Gt CO
2
).
ABSTRACT We compute upper limits on the nanohertz-frequency isotropic stochastic gravitational wave background (GWB) using the 9 year data set from the North American Nanohertz Observatory for ...Gravitational Waves (NANOGrav) collaboration. Well-tested Bayesian techniques are used to set upper limits on the dimensionless strain amplitude (at a frequency of 1 yr−1) for a GWB from supermassive black hole binaries of A gw < 1.5 × 10 − 15 . We also parameterize the GWB spectrum with a broken power-law model by placing priors on the strain amplitude derived from simulations of Sesana and McWilliams et al. Using Bayesian model selection we find that the data favor a broken power law to a pure power law with odds ratios of 2.2 and 22 to one for the Sesana and McWilliams prior models, respectively. Using the broken power-law analysis we construct posterior distributions on environmental factors that drive the binary to the GW-driven regime including the stellar mass density for stellar-scattering, mass accretion rate for circumbinary disk interaction, and orbital eccentricity for eccentric binaries, marking the first time that the shape of the GWB spectrum has been used to make astrophysical inferences. Returning to a power-law model, we place stringent limits on the energy density of relic GWs, gw ( f ) h 2 < 4.2 × 10 − 10 . Our limit on the cosmic string GWB, gw ( f ) h 2 < 2.2 × 10 − 10 , translates to a conservative limit on the cosmic string tension with G < 3.3 × 10 − 8 , a factor of four better than the joint Planck and high-l cosmic microwave background data from other experiments.
The pressure-induced superconductivity and structural evolution of Bi2Se3 single crystals are studied. The emergence of superconductivity at an onset transition temperature (Tc) of about 4.4 K is ...observed at around 12 GPa. Tc increases rapidly to a maximum of 8.2 K at 17.2 GPa, decreases to around 6.5 K at 23 GPa, and then remains almost constant with further increases in pressure. Variations in Tc with respect to pressure are closely related to the carrier density, which increases by over two orders of magnitude from 2 to 23 GPa. High-pressure synchrotron radiation measurements reveal structural transitions at around 12, 20, and above 29 GPa. A phase diagram of superconductivity versus pressure is also constructed.
We report the discovery of a giant planet in the OGLE-2017-BLG-1522 microlensing event. The planetary perturbations were clearly identified by high-cadence survey experiments despite the relatively ...short event timescale of tE ∼ 7.5 days. The Einstein radius is unusually small, θE = 0.065 mas, implying that the lens system either has very low mass or lies much closer to the microlensed source than the Sun, or both. A Bayesian analysis yields component masses and source-lens distance , implying that this is a brown-dwarf/Jupiter system that probably lies in the Galactic bulge, a location that is also consistent with the relatively low lens-source relative proper motion = 3.2 0.5 mas yr−1. The projected companion-host separation is , indicating that the planet is placed beyond the snow line of the host, i.e., asl ∼ 0.12 au. Planet formation scenarios combined with the small companion-host mass ratio q ∼ 0.016 and separation suggest that the companion could be the first discovery of a giant planet that formed in a protoplanetary disk around a brown-dwarf host.
PDF
