Research of the active reflector antenna using laser angle metrology system

Active reflector is one of the key technologies for constructing large telescopes, especially for the millimeter/sub-millimeter radio telescopes. This article introduces a new efficient laser angle metrology system for the active reflector antenna of the large radio telescopes, with a plenty of active reflector experiments mainly about the detecting precisions and the maintaining of the surface shape in real time, on the 65-meter radio telescope prototype constructed by Nanjing Institute of Astronomical Optics and Technology (NIAOT). The test results indicate that the accuracy of the surface shape segmenting and maintaining is up to micron dimension, and the time-response can be of the order of minutes. Therefore, it is proved to be workable for the sub-millimeter radio telescopes.Comment: 10 pages, 15 figure

Layer Antiferromagnetic State in Bilayer Graphene : A First-Principle Investigation

The ground state of bilayer graphene is investigated by the density functional calculations with local spin density approximation. We find a ground state with layer antiferromagnetic ordering, which has been suggested by former studies based on simplified model. The calculations prove that the layer antiferromagnetic state (LAF) is stable even if the remote hopping and nonlocal Coulomb interaction are included. The gap of the LAF state is about 1.8 meV, comparable to the experimental value. The surface magnetism in BLG is of the order of $10^{-2} \mu_B /nm^2$

4-[(2-Hydr­oxy-1-naphth­yl)(piperidin-1-yl)meth­yl]benzonitrile

In the title compound, C23H22N2O, obtained from the condensation reaction of 4-formyl­benzonitrile, 2-naphthol and piperidine, the dihedral angle between the naphthalene ring system and the benzene ring is 75.31 (4)°. The piperidine ring adopts a chair conformation. The crystal structure is stabilized by inter­molecular C—H⋯N hydrogen bonds, which link the mol­ecules into centrosymmetric dimers. An intra­molecular O—H⋯N hydrogen bond is also present

Anderson Impurity in Helical Metal

We use a trial wave function to study the spin-1/2 Kondo effect of a helical metal on the surface of a three-dimensional topological insulator. While the impurity spin is quenched by conduction electrons, the spin-spin correlation of the conduction electron and impurity is strongly anisotropic in both spin and spatial spaces. As a result of strong spin-orbit coupling, the out-of-plane component of the impurity spin is found to be fully screened by the orbital angular momentum of the conduction electrons.Comment: The published versio

8-(4-Nitro­benz­yloxy)quinoline

In the title compound, C16H12N2O3, the planar quinoline ring system [maximum deviation = 0.025 (3) Å] is oriented at a dihedral angle of 61.76 (7)° with respect to the benzene ring. In the crystal structure, inter­molecular C—H⋯O inter­actions link the mol­ecules into chains parallel to the b axis. π–π contacts between the quinoline rings [centroid–centroid distance = 3.623 (1) Å] may further stabilize the structure