Blue Phosphorene Oxide: Strain-tunable Quantum Phase Transitions and Novel 2D Emergent Fermions

Tunable quantum phase transitions and novel emergent fermions in solid state materials are fascinating subjects of research. Here, we propose a new stable two-dimensional (2D) material, the blue phosphorene oxide (BPO), which exhibits both. Based on first-principles calculations, we show that its equilibrium state is a narrow-bandgap semiconductor with three bands at low energy. Remarkably, a moderate strain can drive a semiconductor-to-semimetal quantum phase transition in BPO. At the critical transition point, the three bands cross at a single point at Fermi level, around which the quasiparticles are a novel type of 2D pseudospin-1 fermions. Going beyond the transition, the system becomes a symmetry-protected semimetal, for which the conduction and valence bands touch quadratically at a single Fermi point that is protected by symmetry, and the low-energy quasiparticles become another novel type of 2D double Weyl fermions. We construct effective models characterizing the phase transition and these novel emergent fermions, and we point out several exotic effects, including super Klein tunneling, supercollimation, and universal optical absorbance. Our result reveals BPO as an intriguing platform for the exploration of fundamental properties of quantum phase transitions and novel emergent fermions, and also suggests its great potential in nanoscale device applications.Comment: 23 pages, 5 figure

Preliminary study of predation of the multi-colored lady beetle, Leis axyridis (Pallas), on two species of aphids

Adults of multi-colored lady beetle, Leis axyridis were starved for 24- hour, and allowed to prey on soybean aphid, Aphis glycines Matsumura, and corn leaf aphid, Rhopalosiphum maidis(Fitch) which were at various densities. By comparing and analyzing its predatory potential, we consider that both L. axyridis’ preying on A. glycines and on R. maidis were fitted with type II response, which can be simulated by Holling disc equation, and expressed as: Na 0.6792N/ (1 0.0022N) corn ? ? and Na 0.9463N/ (1 0.0023N) soybean ? ? , respectively. In addition, by comparing its functional parameters, we found that L. axyridis’ ability to control A. glycines is significantly stronger than that of R. maidis.Originating text in Chinese.Citation: Lin, Zhiwei, Wang, Liyan, Sun, Qiang, Nan, Shan. (1999). Preliminary study of predation of the multi-colored lady beetle, Leis axyridis (Pallas), on two species of aphids. Journal of Heilongjiang August First Land Reclamation University, 11(1), 26-28

Preparation of Latent Heat Materials Used in Asphalt Pavement and Theirs' Controlling Temperature Performance

Abstract: In order to solve rutting diseases of asphalt concrete pavement, latent heat materials for asphalt pavement were prepared and theirs' controlling temperature performance were studied. Phase change materials (PCM), which were fitted to thermal environment of road were selected, phase change asphalt, diatomite powder and pottery sand granular composite phase change materials (CPCM) were prepared by three kinds of import modes. The CPCM were chosen by comparing the performance of above mentioned materials. Latent heat asphalt mixture (LHAM) was made by replacing mineral powder and fine aggregate with CPCM. Its controlling temperature ability was tested by temperature monitor system. The results show that, comparing to general asphalt mixture, LHAM can reduce temperature to 8-10℃. Therefore, LHAM has a good effect on adjusting road temperature. Introduction The rutting problem of asphalt concrete pavement has bored road transport administrators in the past few years, it is urgent to seek scientific and effective methods to solve the problem. The asphalt mixture is a viscoelastic material, the main factors which affect its mechanical properties are loading and temperature. Loading conditions are not easy to control, so temperature becomes the dominant factor to solve rutting. For a long time, the researchers have focused on improving temperature stability of asphalt and asphalt mixture, asphalt modifing, adding fiber and optimizing gradation and so on measures have been put forward [1-2]. All methods have changed asphalt pavement's temperature passively. Although they have solved some problems in certain domain and condition, temperature-related diseases of asphalt pavement are still very serious. Therefore, the paper was from the angle of improving temperature status of asphalt pavement, latent heat materials used in asphalt pavement were prepared, theirs' temperature performance were tested. The organic phase change materials (OPCM) were imported into inorganic porous materials to prepare composite phase change materials (CPCM). The latent heat asphalt mixture (LHAM) was prepared by mixing CPCM into asphalt mixture through different channels. CPCM is used to absorb heat of pavement constantly. Because of appropriate phase change temperature and high phase change latent heat, its self-thermostat effect performance is great. Preparation of Latent Heat Materials Used in Asphalt Pavement Phase change materials selection The phase change materials (PCM) can change phase with temperature and provide phase change latent heat (PCLH). Phase change materials can be divided into four categories which are solid-solid, solid-liquid, solid-gas and liquid-ga

Polarization-based probabilistic discriminative model for quantitative characterization of cancer cells

We propose a polarization-based probabilistic discriminative model for deriving a set of new sigmoid-transformed polarimetry feature parameters, which not only enables accurate and quantitative characterization of cancer cells at pixel level, but also accomplish the task with a simple and stable model. By taking advantages of polarization imaging techniques, these parameters enable a low-magnification and wide-field imaging system to separate the types of cells into more specific categories that previously were distinctive under high magnification. Instead of blindly choosing the model, the L0 regularization method is used to obtain the simplified and stable polarimetry feature parameter. We demonstrate the model viability by using the pathological tissues of breast cancer and liver cancer, in each of which there are two derived parameters that can characterize the cells and cancer cells respectively with satisfactory accuracy and sensitivity. The stability of the final model opens the possibility for physical interpretation and analysis. This technique may bypass the typically labor-intensive and subjective tumor evaluating system, and could be used as a blueprint for an objective and automated procedure for cancer cell screening

The cellular source for APOBEC3G's incorporation into HIV-1

<p>Abstract</p> <p>Background</p> <p>Human APOBEC3G (hA3G) has been identified as a cellular inhibitor of HIV-1 infectivity. Viral incorporation of hA3G is an essential step for its antiviral activity. Although the mechanism underlying hA3G virion encapsidation has been investigated extensively, the cellular source of viral hA3G remains unclear.</p> <p>Results</p> <p>Previous studies have shown that hA3G forms low-molecular-mass (LMM) and high-molecular-mass (HMM) complexes. Our work herein provides evidence that the majority of newly-synthesized hA3G interacts with membrane lipid raft domains to form Lipid raft-associated hA3G (RA hA3G), which serve as the precursor of the mature HMM hA3G complex, while a minority of newly-synthesized hA3G remains in the cytoplasm as a soluble LMM form. The distribution of hA3G among the soluble LMM form, the RA LMM form and the mature forms of HMM is regulated by a mechanism involving the N-terminal part of the linker region and the C-terminus of hA3G. Mutagenesis studies reveal a direct correlation between the ability of hA3G to form the RA LMM complex and its viral incorporation.</p> <p>Conclusions</p> <p>Together these data suggest that the Lipid raft-associated LMM A3G complex functions as the cellular source of viral hA3G.</p