scholarly journals Nobeyama 45 m mapping observations toward Orion A. I. Molecular outflows

2019 ◽  
Author(s):  
Yoshihiro Tanabe ◽  
Fumitaka Nakamura ◽  
Takashi Tsukagoshi ◽  
Yoshito Shimajiri ◽  
Shun Ishii ◽  
...  
Keyword(s):  
Energy Dissipation ◽  
Energy Conversion ◽  
Optical Depth ◽  
Molecular Cloud ◽  
Energy Conversion Efficiency ◽  
Total Momentum ◽  
Velocity Range ◽  
Molecular Outflows ◽  
Ejection Rate ◽  
Co Emission

Abstract We conducted an exploration of ${}^{12}$CO molecular outflows in the Orion A giant molecular cloud to investigate outflow feedback using ${}^{12}$CO ($J = 1\!-\!0$) and ${}^{13}$CO ($J = 1\!-\!0$) data obtained by the Nobeyama 45 m telescope. In the region excluding the center of OMC 1, we identified 44 ${}^{12}$CO (including 17 newly detected) outflows based on the unbiased and systematic procedure of automatically determining the velocity range of the outflows and separating the cloud and outflow components. The optical depth of the ${}^{12}$CO emission in the detected outflows is estimated to be approximately 5. The total momentum and energy of the outflows, corrected for optical depth, are estimated to be $1.6 \times 10^{2}\, M_{\odot }\:$km$\:$s$^{-1}$ and $1.5\times 10^{46}\:$erg, respectively. The momentum and energy ejection rate of the outflows are estimated to be 36% and 235% of the momentum and energy dissipation rates of the cloud turbulence, respectively. Furthermore, the ejection rates of the outflows are comparable to those of the expanding molecular shells estimated by Feddersen et al. (2018, ApJ, 862, 121). Cloud turbulence cannot be sustained by the outflows and shells unless the energy conversion efficiency is as high as 20%.

Current progress and performance improvement of Pt/C catalysts for fuel cells

2020 ◽  
Vol 8 (46) ◽  
pp. 24284-24306
Author(s):  
Xuefeng Ren ◽  
Yiran Wang ◽  
Anmin Liu ◽  
Zhihong Zhang ◽  
Qianyuan Lv ◽  
...  
Keyword(s):  
Fuel Cells ◽  
Fuel Cell ◽  
Energy Conversion ◽  
Performance Improvement ◽  
Electric Energy ◽  
Energy Conversion Efficiency ◽  
High Energy ◽  
Carnot Cycle ◽  
High Energy Conversion Efficiency ◽  
And Performance

Fuel cell is an electrochemical device, which can directly convert the chemical energy of fuel into electric energy, without heat process, not limited by Carnot cycle, high energy conversion efficiency, no noise and pollution.

First-principles study on the electronic and optical properties of the orthorhombic CsPbBr3 and CsPbI3 with Cmcm space group

2021 ◽  
Author(s):  
Xianhao Zhao ◽  
Tianyu Tang ◽  
Quan Xie ◽  
like gao ◽  
Limin Lu ◽  
...  
Keyword(s):  
Optical Properties ◽  
Solar Cells ◽  
Energy Conversion ◽  
Conversion Efficiency ◽  
First Principles ◽  
Energy Conversion Efficiency ◽  
Space Group ◽  
Absorbing Materials ◽  
Halide Perovskites ◽  
Lead Halide

The cesium lead halide perovskites are regarded as effective candidates for light-absorbing materials in solar cells, which have shown excellent performances in experiments such as promising energy conversion efficiency. In...

scholarly journals On the scaling of fragmentation and energy dissipation in collisions of dust aggregates

2021 ◽  
Vol 23 (2) ◽  
Author(s):  
Philipp Umstätter ◽  
Herbert M. Urbassek
Keyword(s):  
Energy Dissipation ◽  
Collision Energy ◽  
Velocity Range ◽  
Collision Velocity ◽  
Granular Mechanics ◽  
Extra Factor ◽  
Cluster Fragmentation ◽  
Silica Clusters ◽  
Large Clusters ◽  
Small Clusters

Abstract Fragmentation of granular clusters may be studied by experiments and by granular mechanics simulation. When comparing results, it is often assumed that results can be compared when scaled to the same value of $$E/E_{\mathrm{sep}}$$ E / E sep , where E denotes the collision energy and $$E_{\mathrm{sep}}$$ E sep is the energy needed to break every contact in the granular clusters. The ratio $$E/E_{\mathrm{sep}}\propto v^2$$ E / E sep ∝ v 2 depends on the collision velocity v but not on the number of grains per cluster, N. We test this hypothesis using granular-mechanics simulations on silica clusters containing a few thousand grains in the velocity range where fragmentation starts. We find that a good parameter to compare different systems is given by $$E/(N^{\alpha }E_{\mathrm{sep}})$$ E / ( N α E sep ) , where $$\alpha \sim 2/3$$ α ∼ 2 / 3 . The occurrence of the extra factor $$N^{\alpha }$$ N α is caused by energy dissipation during the collision such that large clusters request a higher impact energy for reaching the same level of fragmentation than small clusters. Energy is dissipated during the collision mainly by normal and tangential (sliding) forces between grains. For large values of the viscoelastic friction parameter, we find smaller cluster fragmentation, since fragment velocities are smaller and allow for fragment recombination. Graphic abstract

scholarly journals Optical Parametric Oscillation with Ultra-low Power Threshold in a Dimer of Active-Passive Cavities

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 566
Author(s):  
Bo Lu ◽  
Chen-Rui Fan ◽  
Jun-Yang Song ◽  
Chuan Wang
Keyword(s):  
Pump Power ◽  
Energy Conversion ◽  
Energy Conversion Efficiency ◽  
Parametric Oscillation ◽  
Optical Parametric Oscillation ◽  
Optical Parametric ◽  
Non Linear ◽  
Oscillation Process ◽  
Power Threshold ◽  
Low Threshold

Optical parametric oscillation can convert the input laser into a couple of coherent optical output with signal and idler frequencies. It is an important method for the realization of the broadband middle infrared tunable lasers. The optical parametric oscillation process depends on the ultra-fast non-linear response of matter to light with a certain pump power. Therefore, reducing the pump threshold of the optical parametric oscillation process and improving the energy conversion efficiency are of great significance to the study of non-linear optics. In this paper, we construct a dimer system that couples a passive non-linear resonator to an active resonator. Based on the dimer system, an ultra-low threshold optical parametric oscillation generation method is proposed. By coupling the gain pump mode, the non-linear effect is effectively enhanced, the pump power threshold is reduced to half of when there is no gain, and the energy conversion efficiency is increased. We believe this research provides a feasible method for a low-threshold tunable and easy-to-integrate optical parametric oscillation laser source.

scholarly journals Carbon-chain molecules in molecular outflows and Lupus I region – new producing region and new forming mechanism

2019 ◽  
Vol 488 (1) ◽  
pp. 495-511
Author(s):  
Yuefang Wu ◽  
Xunchuan Liu ◽  
Xi Chen ◽  
Lianghao Lin ◽  
Jinghua Yuan ◽  
...  
Keyword(s):  
Radio Telescope ◽  
Molecular Cloud ◽  
Carbon Chain ◽  
Species Range ◽  
Chain Molecules ◽  
Forming Mechanism ◽  
Molecular Outflows ◽  
Chemical Models ◽  
Cloud Complex

Abstract Using the new equipment of the Shanghai Tian Ma Radio Telescope, we have searched for carbon-chain molecules (CCMs) towards five outflow sources and six Lupus I starless dust cores, including one region known to be characterized by warm carbon-chain chemistry (WCCC), Lupus I-1 (IRAS 15398-3359), and one TMC-1 like cloud, Lupus I-6 (Lupus-1A). Lines of HC3N J = 2 − 1, HC5N J = 6 − 5, HC7N J = 14 − 13, 15 − 14, 16 − 15, and C3S J = 3 − 2 were detected in all the targets except in the outflow source L1660 and the starless dust core Lupus I-3/4. The column densities of nitrogen-bearing species range from 1012 to 1014 cm−2 and those of C3S are about 1012 cm−2. Two outflow sources, I20582+7724 and L1221, could be identified as new carbon-chain-producing regions. Four of the Lupus I dust cores are newly identified as early quiescent and dark carbon-chain-producing regions similar to Lup I-6, which together with the WCCC source, Lup I-1, indicate that carbon-chain-producing regions are popular in Lupus I which can be regard as a Taurus-like molecular cloud complex in our Galaxy. The column densities of C3S are larger than those of HC7N in the three outflow sources I20582, L1221, and L1251A. Shocked carbon-chain chemistry is proposed to explain the abnormal high abundances of C3S compared with those of nitrogen-bearing CCMs. Gas-grain chemical models support the idea that shocks can fuel the environment of those sources with enough S+ thus driving the generation of S-bearing CCMs.

scholarly journals 13CO(J = 1-0) Observations of the Orion Molecular Cloud

1987 ◽  
Vol 115 ◽  
pp. 149-150
Author(s):  
K. Sugitani ◽  
Y. Fukui
Keyword(s):  
Millimeter Wave ◽  
High Velocity ◽  
Molecular Cloud ◽  
High Velocity Resolution ◽  
H Ii Region ◽  
Co Emission

We present new 13CO(J = 1-0) measurements of the Orion molecular cloud. The data were taken with the 4-m millimeter-wave telescope of Nagoya University with a beamwidth of 2.7′. The high velocity resolution of 0.1 km s−1 employed has revealed significant details of the 13CO emission toward the H II region.

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