Highly tunable thermal emitter with vanadium dioxidemetamaterials for radiative cooling

2021 ◽  
Author(s):  
Yuanlin Jia ◽  
Xiaoxia Wang ◽  
Huaiyuan Yin ◽  
Huawei Yao ◽  
junqiao Wang ◽  
...  
Keyword(s):  
Radiative Cooling ◽  
Thermal Emitter

Realization of efficient radiative cooling in thermal emitter with inorganic metamaterials

2021 ◽  
Author(s):  
Huaiyuan Yin ◽  
Huawei Yao ◽  
Yuanlin Jia ◽  
Junqiao Wang ◽  
Chunzhen Fan
Keyword(s):  
Radiative Cooling ◽  
Thermal Emitter

Efficient Thin Polymer Coating as a Selective Thermal Emitter for Passive Daytime Radiative Cooling

2021 ◽  
Author(s):  
Udayan Banik ◽  
Ashutosh Agrawal ◽  
Hosni Meddeb ◽  
Oleg Sergeev ◽  
Nies Reininghaus ◽  
...  
Keyword(s):  
Polymer Coating ◽  
Radiative Cooling ◽  
Thin Polymer ◽  
Thermal Emitter ◽  
Selective Thermal Emitter

Janus thermal emitter by spoof surface plasmon polariton for radiative cooling

2020 ◽  
Author(s):  
Gil Ju Lee ◽  
Se-Yeon Heo ◽  
Do Hyeon Kim ◽  
Yeong Jae Kim ◽  
Min Seok Kim ◽  
...  
Keyword(s):  
Surface Plasmon ◽  
Surface Plasmon Polariton ◽  
Radiative Cooling ◽  
Thermal Emitter ◽  
Plasmon Polariton

scholarly journals Ultra-broadband all-dielectric metamaterial thermal emitter for passive radiative cooling

2019 ◽  
Vol 27 (21) ◽  
pp. 30102 ◽  
Author(s):  
Aru Kong ◽  
Boyuan Cai ◽  
Peng Shi ◽  
Xiao-cong Yuan
Keyword(s):  
Radiative Cooling ◽  
Thermal Emitter

Low-workfunction field-emission source for high-resolution EELS

1987 ◽  
Vol 45 ◽  
pp. 132-133
Author(s):  
P. E. Batson
Keyword(s):  
High Resolution ◽  
Energy Loss ◽  
Electron Probe ◽  
Collection Efficiency ◽  
Electron Sources ◽  
Wien Filter ◽  
Half Angle ◽  
Thermal Emitter ◽  
Electron Energy Loss ◽  
Intrinsic Energy

In recent years,instrumentation for electron energy loss spectroscopy (EELS) has been steadily improved to increase energy resolution and collection efficiency. At present 0.40eV at 10mR collection half angle is available with commercial magnetic sectors (e.g. Gatan, Inc. and VG Microscopes, Ltd.), and 70meV at 10mR has been demonstrated by use of a Wien filter within a large deceleration field. When these high resolution spectrometers are coupled to the modern small electron probe instrument, we obtain a tool which promises to reveal local changes in bandstructure and bonding near defects and interfaces in heterogeneous materials.Unfortunately, typical electron sources have intrinsic energy widths which limit attainable spectroscopic resolution in the absence of some monochromation system. For instance, the W thermal emitter has a half width of about 1eV.

Saturation mechanism and generated viscosity in gravito-turbulent accretion disks

2020 ◽  
Vol 640 ◽  
pp. A53
Author(s):  
L. Löhnert ◽  
S. Krätschmer ◽  
A. G. Peeters
Keyword(s):  
Growth Rate ◽  
Numerical Simulations ◽  
Accretion Disks ◽  
Gravitational Instability ◽  
Turbulent Viscosity ◽  
Radial Distance ◽  
Maximum Growth ◽  
Wave Number ◽  
Radiative Cooling ◽  
Mixing Length

Here, we address the turbulent dynamics of the gravitational instability in accretion disks, retaining both radiative cooling and irradiation. Due to radiative cooling, the disk is unstable for all values of the Toomre parameter, and an accurate estimate of the maximum growth rate is derived analytically. A detailed study of the turbulent spectra shows a rapid decay with an azimuthal wave number stronger than ky−3, whereas the spectrum is more broad in the radial direction and shows a scaling in the range kx−3 to kx−2. The radial component of the radial velocity profile consists of a superposition of shocks of different heights, and is similar to that found in Burgers’ turbulence. Assuming saturation occurs through nonlinear wave steepening leading to shock formation, we developed a mixing-length model in which the typical length scale is related to the average radial distance between shocks. Furthermore, since the numerical simulations show that linear drive is necessary in order to sustain turbulence, we used the growth rate of the most unstable mode to estimate the typical timescale. The mixing-length model that was obtained agrees well with numerical simulations. The model gives an analytic expression for the turbulent viscosity as a function of the Toomre parameter and cooling time. It predicts that relevant values of α = 10−3 can be obtained in disks that have a Toomre parameter as high as Q ≈ 10.

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