Normal density and moment of inertia of a moving superfluid

In this work, the normal density $\rho_n$ and moment of inertia of a moving superfluid are investigated. We find that, even at zero temperature, there exists a finite normal density for the moving superfluid. When the velocity of superfluid reaches sound velocity, the normal density becomes total mass density $\rho$, which indicates that the system losses superfluidity. At the same time, the Landau's critical velocity also becomes zero. The existence of the non-zero normal density is attributed to the coupling between the motion of superflow and density fluctuation in transverse directions. With Josephson relation, the superfluid density $\rho_s$ is also calculated and the identity $\rho_s+\rho_n=\rho$ holds. Further more, we find that the finite normal density also results in a quantized moment of inertia in a moving superfluid trapped by a ring. The normal density and moment of inertia at zero temperature could be verified experimentally by measuring the angular momentum of a moving superfluid in a ring trap.Comment: 6 page

Paraboea yunfuensis: a new calcicolous species of Gesneriaceae from Yunfu, Guangdong Province, China

Paraboea yunfuensis F.Wen & Y.G.Wei (Gesneriaceae) is described as a new species endemic to the Guangdong Province, China. This species is one of two peltate-leaved Paraboea species in China. It is distinguished from the similar-looking P. peltifolia by the presence of longer pedicel and filaments, shorter staminodes, linear-lanceolate calyx lobes, and an indumentum on peduncles, pedicels, and calyx lobes. A detailed description, photographs of a specimen from the type location, and a table of comparative characters are provided

Topological superconductivity and large spin Hall effect in the kagome family Ti6X4 (X = Bi, Sb, Pb, Tl, In)

Topological superconductors (TSC) become a focus of research due to the accompanying Majorana fermions. However, the experimentally reported TSC are extremely rare. The recent experiments reported the kagome TSC AV$_{3}$Sb$_{5}$ (A=K, Rb, Cs), which exhibit unique superconductivity, topological surface states (TSS), and Majorana bound states. More recently, the first titanium-based kagome superconductor CsTi$_{3}$Bi$_{5}$ with nontrivial topology was successfully synthesized as a perspective TSC. Given that Cs contributes little to the electronic structures of CsTi$_{3}$Bi$_{5}$ and binary compounds may be easier to be synthesized, here, by density functional theory calculations, we predict five stable non-magnetic kagome compounds Ti$_{6}$X$_{4}$ (X = Bi, Sb, Pb, Tl, In) which exhibit superconductivity with critical temperature Tc = 3.8$-$5.1 K, nontrivial $\mathbb{Z}$$_2$ band topology, and TSS close to the Fermi level. In addition, the large intrinsic spin Hall effect is obtained in Ti$_{6}$X$_{4}$, which is caused by gapped Dirac nodes and nodal lines due to a strong spin-orbit coupling. This work offers new platforms for TSC and spintronic devices

Auction design for the allocation of carbon emission allowances: uniform or discriminatory price?

Only four states used auction in Phase Ⅰ (2005-2007) of the European Union Emission Trading System, of which four used a uniform-price sealed auction format. Here we discuss whether the auction should adopt a uniform-price or discriminatory-price format using an agent-based carbon allowances auction model established for the purpose. The main conclusions are as follows: (1) when carbon allowances are relatively scarce, the government should use a discriminatory-price auction; when carbon allowances are relatively abundant, the government should use a uniform-price auction. (2) Uncertainty of the generating cost reduces the ability of an auction to know bidders’ private values, which will reduce the government’s revenue and reduce auction efficiency. (3) Compared with the discriminatory-price auction, the uniform-price auction can prevent large bidders from obtaining excessive profits. (4) The uniform-price auction is relatively insensitive to market structure. However, a monopoly market is more likely to develop under the discriminatory-price auction format. The results of the model have some policy implications for designing carbon market mechanisms in the future

Potential impact of (CET) carbon emissions trading on China’s power sector: A perspective from different allowance allocation options

In Copenhagen climate conference China government promised that China would cut down carbon intensity 40e45% from 2005 by 2020. CET (carbon emissions trading) is an effective tool to reduce emissions. But because CET is not fully implemented in China up to now, how to design it and its potential impact are unknown to us. This paper studies the potential impact of introduction of CET on China’s power sector and discusses the impact of different allocation options of allowances. Agent-based modeling is one appealing new methodology that has the potential to overcome some shortcomings of traditional methods. We establish an agent-based model, CETICEM (CET Introduced China Electricity Market), of introduction of CET to China. In CETICEM, six types of agents and two markets are modeled. We find that: (1) CET internalizes environment cost; increases the average electricity price by 12%; and transfers carbon price volatility to the electricity market, increasing electricity price volatility by 4%. (2) CET influences the relative cost of different power generation technologies through the carbon price, significantly increasing the proportion of environmentally friendly technologies; expensive solar power generation in particular develops significantly, with final proportion increasing by 14%. (3) Emissionbased allocation brings about both higher electricity and carbon prices than by output-based allocation which encourages producers to be environmentally friendly. Therefore, output-based allocation would be more conducive to reducing emissions in the Chinese power sector

Potential impact of (CET) carbon emissions trading on China’s power sector: A perspective from different allowance allocation options

In Copenhagen climate conference China government promised that China would cut down carbon intensity 40e45% from 2005 by 2020. CET (carbon emissions trading) is an effective tool to reduce emissions. But because CET is not fully implemented in China up to now, how to design it and its potential impact are unknown to us. This paper studies the potential impact of introduction of CET on China’s power sector and discusses the impact of different allocation options of allowances. Agent-based modeling is one appealing new methodology that has the potential to overcome some shortcomings of traditional methods. We establish an agent-based model, CETICEM (CET Introduced China Electricity Market), of introduction of CET to China. In CETICEM, six types of agents and two markets are modeled. We find that: (1) CET internalizes environment cost; increases the average electricity price by 12%; and transfers carbon price volatility to the electricity market, increasing electricity price volatility by 4%. (2) CET influences the relative cost of different power generation technologies through the carbon price, significantly increasing the proportion of environmentally friendly technologies; expensive solar power generation in particular develops significantly, with final proportion increasing by 14%. (3) Emissionbased allocation brings about both higher electricity and carbon prices than by output-based allocation which encourages producers to be environmentally friendly. Therefore, output-based allocation would be more conducive to reducing emissions in the Chinese power sector