3,629 research outputs found

    A Study of Social Support for Patients with Mental Disorders in Rehabilitation Stations

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     In recent years, the prevalence of mental disorders has increased dramatically and has become a disease that seriously endangers people’s physical and mental health. According to the World Health Organization (WHO), about 1 billion people worldwide are suffering from mental disorders. However, the social organizations specializing in serving people with mental disorders in China are inadequate and have limited power, and the cooperative ties among welfare providers are not close enough, which cause the failing to provide efficient support and services for people with mental disorders. This study adopts a field research method to explore the complementary cooperative relationship among various welfare providers and the social support received by patients with mental disorders in the rehabilitation process, and to promote the social support role of various welfare providers in education, employment and medical care in the welfare services for the group of patients with mental disorders, using 17 rehabilitation stations in Suzhou City A District as the research subjects.

    A multi-protein receptor-ligand complex underlies combinatorial dendrite guidance choices in C. elegans.

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    Ligand receptor interactions instruct axon guidance during development. How dendrites are guided to specific targets is less understood. The C. elegans PVD sensory neuron innervates muscle-skin interface with its elaborate dendritic branches. Here, we found that LECT-2, the ortholog of leukocyte cell-derived chemotaxin-2 (LECT2), is secreted from the muscles and required for muscle innervation by PVD. Mosaic analyses showed that LECT-2 acted locally to guide the growth of terminal branches. Ectopic expression of LECT-2 from seam cells is sufficient to redirect the PVD dendrites onto seam cells. LECT-2 functions in a multi-protein receptor-ligand complex that also contains two transmembrane ligands on the skin, SAX-7/L1CAM and MNR-1, and the neuronal transmembrane receptor DMA-1. LECT-2 greatly enhances the binding between SAX-7, MNR-1 and DMA-1. The activation of DMA-1 strictly requires all three ligands, which establishes a combinatorial code to precisely target and pattern dendritic arbors

    The Third Law of Quantum Thermodynamics in the Presence of Anomalous Couplings

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    The quantum thermodynamic functions of a harmonic oscillator coupled to a heat bath through velocity-dependent coupling are obtained analytically. It is shown that both the free energy and the entropy decay fast with the temperature in relation to that of the usual coupling from. This implies that the velocity-dependent coupling helps to ensure the third law of thermodynamics.Comment: 4 pages, 3 figures, 22 conference

    Statistics of temperature and thermal energy dissipation rate in low-Prandtl number turbulent thermal convection

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    We report the statistical properties of temperature and thermal energy dissipation rate in low-Prandtl number turbulent Rayleigh-B\'enard convection. High resolution two-dimensional direct numerical simulations were carried out for the Rayleigh number (RaRa) of 106≤Ra≤10710^{6} \le Ra \le 10^{7} and the Prandtl number (PrPr) of 0.025. Our results show that the global heat transport and momentum scaling in terms of Nusselt number (NuNu) and Reynolds number (ReRe) are Nu=0.21Ra0.25Nu=0.21Ra^{0.25} and Re=6.11Ra0.50Re=6.11Ra^{0.50}, respectively, indicating that the scaling exponents are smaller than those for moderate-Prandtl number fluids (such as water or air) in the same convection cell. In the central region of the cell, probability density functions (PDFs) of temperature profiles show stretched exponential peak and the Gaussian tail; in the sidewall region, PDFs of temperature profiles show a multimodal distribution at relative lower RaRa, while they approach the Gaussian profile at relative higher RaRa. We split the energy dissipation rate into contributions from bulk and boundary layers and found the locally averaged thermal energy dissipation rate from the boundary layer region is an order of magnitude larger than that from the bulk region. Even if the much smaller volume occupied by the boundary layer region is considered, the globally averaged thermal energy dissipation rate from the boundary layer region is still larger than that from the bulk region. We further numerically determined the scaling exponents of globally averaged thermal energy dissipation rates as functions of RaRa and ReRe.Comment: 21 pages. 8 figure

    Wall-sheared thermal convection: heat transfer enhancement and turbulence relaminarization

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    We studied the flow organization and heat transfer properties in two-dimensional and three-dimensional Rayleigh-B\'enard cells that are imposed with different types of wall shear. The external wall shear is added with the motivation of manipulating flow mode to control heat transfer efficiency. We imposed three types of wall shear that may facilitate the single-roll, the horizontally stacked double-roll, and the vertically stacked double-roll flow modes, respectively. Direct numerical simulations are performed for fixed Rayleigh number Ra=108Ra = 10^{8} and fixed Prandtl number Pr=5.3Pr = 5.3, while the wall-shear Reynolds number (RewRe_{w}) is in the range 60≤Rew≤600060 \le Re_{w} \le 6000. Generally, we found enhanced heat transfer efficiency and global flow strength with the increase of RewRe_{w}. However, even with the same magnitude of global flow strength, the heat transfer efficiency varies significantly when the cells are under different types of wall shear. An interesting finding is that by increasing the wall-shear strength, the thermal turbulence is relaminarized, and more surprisingly, the heat transfer efficiency in the laminar state is higher than that in the turbulent state. We found that the enhanced heat transfer efficiency at the laminar regime is due to the formation of more stable and stronger convection channels. We propose that the origin of thermal turbulence laminarization is the reduced amount of thermal plumes. Because plumes are mainly responsible for turbulent kinetic energy production, when the detached plumes are swept away by the wall shear, the reduced number of plumes leads to weaker turbulent kinetic energy production. We also quantify the efficiency of facilitating heat transport via external shearing, and find that for larger RewRe_{w}, the enhanced heat transfer efficiency comes at a price of a larger expenditure of mechanical energy.Comment: 27 pages, 16 figure

    Pore-scale statistics of temperature and thermal energy dissipation rate in turbulent porous convection

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    We report pore-scale statistical properties of temperature and thermal energy dissipation rate in a two-dimensional porous Rayleigh-B\'enard (RB) cell. High-resolution direct numerical simulations were carried out for the fixed Rayleigh number (RaRa) of 10910^{9} and the Prandtl numbers (PrPr) of 5.3 and 0.7. We consider sparse porous media where the solid porous matrix is impermeable to both fluid and heat flux. The porosity (ϕ\phi) range 0.86≤ϕ≤0.980.86 \leq \phi \le 0.98, the corresponding Darcy number (DaDa) range 10−4<Da<10−210^{-4}<Da<10^{-2} and the porous Rayleigh number (Ra∗=Ra⋅DaRa^{*}=Ra\cdot Da) range 105<Ra∗<10710^{5} < Ra^{*} < 10^{7}. Our results indicate that the plume dynamics in porous RB convection are less coherent when the solid porous matrix is impermeable to heat flux, as compared to the case where it is permeable. The averaged vertical temperature profiles remain almost a constant value in the bulk, whilst the mean square fluctuations of temperature increases with decreasing porosity. Furthermore, the absolute values of skewness and flatness of the temperature are much smaller in the porous RB cell than in the canonical RB cell. We found that intense thermal energy dissipation occurs near the top and bottom walls, as well as in the bulk region of the porous RB cell. In comparison with the canonical RB cell, the small-scale thermal energy dissipation field is more intermittent in the porous cell, although both cells exhibit a non-log-normal distribution of thermal energy dissipation rate. This work highlights the impact of impermeable solid porous matrices on the statistical properties of temperature and thermal energy dissipation rate, and the findings may have practical applications in geophysics, energy and environmental engineering, as well as other fields that involve the transport of heat through porous media.Comment: 30 pages, 16 figure

    Transport and deposition of dilute microparticles in turbulent thermal convection

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    We analyze the transport and deposition behavior of dilute microparticles in turbulent Rayleigh-B\'enard convection. Two-dimensional direct numerical simulations were carried out for the Rayleigh number (RaRa) of 10810^{8} and the Prandtl number (PrPr) of 0.71 (corresponding to the working fluids of air). The Lagrangian point particle model was used to describe the motion of microparticles in the turbulence. Our results show that the suspended particles are homogeneously distributed in the turbulence for the Stokes number (StSt) less than 10−310^{-3}, and they tend to cluster into bands for 10−3≲St≲10−210^{-3} \lesssim St \lesssim 10^{-2}. At even larger StSt, the microparticles will quickly sediment in the convection. We also calculate the mean-square displacement (MSD) of the particle's trajectories. At short time intervals, the MSD exhibits a ballistic regime, and it is isotropic in vertical and lateral directions; at longer time intervals, the MSD reflects a confined motion for the particles, and it is anisotropic in different directions. We further obtained a phase diagram of the particle deposition positions on the wall, and we identified three deposition states depending on the particle's density and diameter. An interesting finding is that the dispersed particles preferred to deposit on the vertical wall where the hot plumes arise, which is verified by tilting the cell and altering the rotation direction of the large-scale circulation.Comment: 21 pages, 10 figure
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