412 research outputs found
Extraction of Plumes in Turbulent Thermal Convection
We present a scheme to extract information about plumes, a prominent coherent
structure in turbulent thermal convection, from simultaneous local velocity and
temperature measurements. Using this scheme, we study the temperature
dependence of the plume velocity and understand the results using the equations
of motion. We further obtain the average local heat flux in the vertical
direction at the cell center. Our result shows that heat is not mainly
transported through the central region but instead through the regions near the
sidewalls of the convection cell.Comment: 4 pages, 4 figures, submitted to Physical Review Letter
PO-234 Research progress of exercise therapy on type 1 diabetes mellitus
Objective Type 1 diabetes mellitus (T1DM) is an autoimmune disease with a clear genetic basis, and early islet cell function appears clearly in recession or even lost. Insulin deficiency allows patients to rely on exogenous insulin for life, and long-term complications seriously affect quality of life and shorten life expectancy.
Methods This paper retrieves 1998-2018 years' literatures on "Sports" and "type 1 diabetes" through the PubMed database, and collate and analyze the progress of the research and induction of type 1 diabetes exercise therapy.
Results Numerous studies have shown that regular physical exercise can reduce the daily insulin dose in patients with T1DM.At the same time, they should master the contraindications in order to avoid the risks of movement. Currently a recommendation for all T1DM patients is engaging in at least 150 min/week of moderate to vigorous intensity aerobic exercise, sustainability or HIIT, combined with resistance training such as resistance machines and bands, as well as other stretching and balance exercises such as yoga, tai chi, 3 to 7 times per week which is depended on the physical condition of patients and exercise intensity, and resistance training can be performed on nonconsecutive days.
Conclusions So patients need to be clear how to safely increase their physical activity, and incorporate more independent physical activity into daily life.
 
Experimental observation of highly anisotropic elastic properties of two-dimensional black arsenic
Anisotropic two-dimensional layered materials with low-symmetric lattices
have attracted increasing attention due to their unique orientation-dependent
mechanical properties. Black arsenic (b-As), with the puckered structure,
exhibits extreme in-plane anisotropy in optical, electrical and thermal
properties. However, experimental research on mechanical properties of b-As is
very rare, although theoretical calculations predicted the exotic elastic
properties of b-As, such as anisotropic Young's modulus and negative Poisson's
ratio. Herein, experimental observations on highly anisotropic elastic
properties of b-As were demonstrated using our developed in situ tensile
straining setup based on the effective microelectromechanical system. The
cyclic and repeatable load-displacement curves proved that Young's modulus
along zigzag direction was ~1.6 times greater than that along armchair
direction, while the anisotropic ratio of ultimate strain reached ~2.5,
attributed to hinge structure in armchair direction. This study could provide
significant insights to design novel anisotropic materials and explore their
potential applications in nanomechanics and nanodevices.Comment: 19 pages, 5 figure
Highly Anisotropic Elastic Properties of Suspended Black Arsenic Nanoribbons
Anisotropy, as an exotic degree of freedom, enables us to discover the
emergent two-dimensional (2D) layered nanomaterials with low in-plane symmetry
and to explore their outstanding properties and promising applications. 2D
black arsenic (b-As) with puckered structure has garnered increasing attention
these years owing to its extreme anisotropy with respect to the electrical,
thermal, and optical properties. However, the investigation on mechanical
properties of 2D b-As is still lacking, despite much effort on theoretical
simulations. Herein, we report the highly anisotropic elastic properties of
suspended b-As nanoribbons via atomic force microscope-based nanoindentation.
It was found that the extracted Young's modulus of b-As nanoribbons exhibits
remarkable anisotropy, which approximates to 72.2 +- 5.4 and 44.3 +- 1.4 GPa
along zigzag and armchair directions, respectively. The anisotropic ratio
reaches up to ~ 1.6. We expect that these results could lay a solid foundation
for the potential applications of 2D anisotropic nanomaterials in the
next-generation nanomechanics and optoelectronics.Comment: 17 pages, 5 figure
GW25-e1160 Detection of right-to-left shunt in secundum atrial septal defect without severe pulmonary hypertension by saline contrast
Gate-Compatible Circuit QED in a Three-Dimensional Cavity Architecture
Semiconductor-based superconducting qubits offer a versatile platform for
studying hybrid quantum devices in circuit quantum electrodynamics (cQED)
architecture. Most of these cQED experiments utilize coplanar waveguides, where
the incorporation of DC gate lines is straightforward. Here, we present a
technique for probing gate-tunable hybrid devices using a three-dimensional
(3D) microwave cavity. A recess is machined inside the cavity wall for the
placement of devices and gate lines. We validate this design using a hybrid
device based on an InAs-Al nanowire Josephson junction. The coupling between
the device and the cavity is facilitated by a long superconducting strip, the
antenna. The Josephson junction and the antenna together form a gatemon qubit.
We further demonstrate the gate-tunable cavity shift and two-tone qubit
spectroscopy. This technique could be used to probe various quantum devices and
materials in a 3D cQED architecture that requires DC gate voltages
Hard superconducting gap in PbTe nanowires
Semiconductor nanowires coupled to a superconductor provide a powerful
testbed for quantum device physics such as Majorana zero modes and gate-tunable
hybrid qubits. The performance of these quantum devices heavily relies on the
quality of the induced superconducting gap. A hard gap, evident as vanishing
subgap conductance in tunneling spectroscopy, is both necessary and desired.
Previously, a hard gap has been achieved and extensively studied in III-V
semiconductor nanowires (InAs and InSb). In this study, we present the
observation of a hard superconducting gap in PbTe nanowires coupled to a
superconductor Pb. The gap size () is 1 meV (maximally 1.3 meV
in one device). Additionally, subgap Andreev bound states can also be created
and controlled through gate tuning. Tuning a device into the open regime can
reveal Andreev enhancement of the subgap conductance, suggesting a remarkable
transparent superconductor-semiconductor interface, with a transparency of
0.96. These results pave the way for diverse superconducting quantum
devices based on PbTe nanowires
Ballistic PbTe Nanowire Devices
Disorder is the primary obstacle in current Majorana nanowire experiments.
Reducing disorder or achieving ballistic transport is thus of paramount
importance. In clean and ballistic nanowire devices, quantized conductance is
expected with plateau quality serving as a benchmark for disorder assessment.
Here, we introduce ballistic PbTe nanowire devices grown using the
selective-area-growth (SAG) technique. Quantized conductance plateaus in units
of are observed at zero magnetic field. This observation represents an
advancement in diminishing disorder within SAG nanowires, as none of the
previously studied SAG nanowires (InSb or InAs) exhibit zero-field ballistic
transport. Notably, the plateau values indicate that the ubiquitous valley
degeneracy in PbTe is lifted in nanowire devices. This degeneracy lifting
addresses an additional concern in the pursuit of Majorana realization.
Moreover, these ballistic PbTe nanowires may enable the search for clean
signatures of the spin-orbit helical gap in future devices
High Prevalence and Genetic Diversity of HCV among HIV-1 Infected People from Various High-Risk Groups in China
BACKGROUND: Co-infection with HIV-1 and HCV is a significant global public health problem and a major consideration for anti-HIV-1 treatment. HCV infection among HIV-1 positive people who are eligible for the newly launched nationwide anti-HIV-1 treatment program in China has not been well characterized. METHODOLOGY: A nationwide survey of HIV-1 positive injection drug uses (IDU), former paid blood donors (FBD), and sexually transmitted cases from multiple provinces including the four most affected provinces in China was conducted. HCV prevalence and genetic diversity were determined. We found that IDU and FBD have extremely high rates of HCV infection (97% and 93%, respectively). Surprisingly, people who acquired HIV-1 through sexual contact also had a higher rate of HCV infection (20%) than the general population. HIV-1 subtype and HCV genotypes were amazingly similar among FBD from multiple provinces stretching from Central to Northeast China. However, although patterns of overland trafficking of heroin and distinct HIV-1 subtypes could be detected among IDU, HCV genotypes of IDU were more diverse and exhibited significant regional differences. CONCLUSION: Emerging HIV-1 and HCV co-infection and possible sexual transmission of HCV in China require urgent prevention measures and should be taken into consideration in the nationwide antiretroviral treatment program
- …