Spontaneous Ferromagnetism Induced Topological Transition in EuB_{6}.

The interplay between various symmetries and electronic bands topology is one of the core issues for topological quantum materials. Spontaneous magnetism, which leads to the breaking of time-reversal symmetry, has been proven to be a powerful approach to trigger various exotic topological phases. In this Letter, utilizing the combination of angle-resolved photoemission spectroscopy, magneto-optical Kerr effect microscopy, and first-principles calculations, we present the direct evidence on the realization of the long-sought spontaneous ferromagnetism induced topological transition in soft ferromagnetic EuB_{6}. Explicitly, we reveal the topological transition is from Z_{2}=1 topological insulator in paramagnetic state to χ=1 magnetic topological semimetal in low temperature ferromagnetic state. Our results demonstrate that the simple band structure near the Fermi level and rich topological phases make EuB_{6} an ideal platform to study the topological phase physics.

[Survey of HIV infection in men who have sex with men living for 5 years or less in Wenzhou, Zhejiang province].

Objective: To assess the prevalence of HIV infection and related factors in men who have sex with men (MSM) living for ≤5 years in Wenzhou of Zhejiang province. Methods: MSM who were aged ≥16 years, had lived in Wenzhou for ≥3 months and had anal sex and/or oral sex with men in the last 12 months were recruited through respondent-driven sampling (RDS) from February to October in 2015. The MSM recruited completed a questionnaire for the information collection on socio-demographic characteristics, sexual behavior, awareness of HIV and related intervention, mental health status. Blood samples were collected from them for serological detection of HIV and syphilis antibodies. Software SPSS 18.0 was used to analyze HIV infection and related factors. Results: A total of 454 MSM were investigated, 108 of them (23.7%) were HIV positive. There were 267 MSM who lived in Wenzhou for ≤5 years, and 73 of them (27.3%) were HIV positive. Most of them were workers and commercial servants aged ≥25 years with personal monthly income <4 000 yuan and educational level of junior high school or below. According to multiple logistics regression analysis, age of 25-68 years old (OR=12.19, 95%CI: 2.29-65.02), heterosexual behavior in recent 6 months (OR=0.42, 95%CI: 0.18-0.96), believing it was possible to be infected with HIV (OR=0.06, 95%CI: 0.01-0.95), believing it was impossible to be infected with HIV (OR=0.03, 95%CI: 0.01-0.35) and syphilis status (OR=3.32, 95%CI: 1.05-10.52) were the risk factors associated with HIV infection. Conclusion: Compared with MSM who lived in Wenzhou for >5 years, MSM who lived in Wenzhou for ≤5 years had higher HIV infection rate and higher prevalence of risk behavior. It is necessary to conduct targeted intervention among them.

Microwave absorption of gamma'-Fe2.6 Ni1.4N nanoparticles derived from nitriding counterpart precursor.

Gamma-Fe2.6Ni1.4 nanoparticles were prepared by the arc-discharge method as the precursor and its nitride counterpart of gamma'-Fe2.6Ni14N nanoparticles was synthesized directly through a thermal ammonolysis reaction at the temperature of 673 K for two hours. The resultant product was identified as a homogeneous ternary nitride with nearly spherical shape and average size of about 60.0 nm. The electromagnetic characteristics of gamma'-Fe2.6Ni1.4N derivant and gamma-Fe2.6Ni1.4 precursor have been studied in the frequency range of 2-18 GHz. Compared with the precursor, gamma'-Fe2.6Ni1.4N nanoparticles exhibits an enhanced electromagnetic absorption property resulted from the increased dielectric loss by nitriding process. The optimal reflection loss (RL) of gamma'-Fe2.6Ni1.4N nanoparticles/paraffin composite can reach -39.9 dB at 5.2 GHz in a thickness of 2.29 mm, and the frequency band corresponding RL < -10 dB is over 2.6-18 GHz in the thickness range of 0.78-4.20 mm.

Direct electrodeposition of highly dense Bi/Sb superlattice nanowire arrays.

Ordered arrays of Bi/Sb superlattice nanowires with diameters of about 50 nm have been produced by pulsed electrodeposition technique into the pores of anodic alumina membrane (AAM). The structure of Bi/Sb superlattice nanowire can be modulated by controlling the electrodeposition conditions.