The chemical reactivity of graphene doped by B or N (B/N-G) toward H adatom has been studied systematically using density functional theory. From the site dependence of the adsorption energy of hydrogen adatom, the nonlocal and local charge-doping effects and local strain effect of B and N impurities on the chemical reactivity of graphene are derived. The nonlocal doping charges originate from nonlocal aromatic electron resonance, but the local doping charges are bonded to the vicinity of B/N dopant as a result of its high/low inherent chemical potential. Both of nonlocal and local charge-doping effects coexist in B-doped or N-doped graphene, while the nonlocal charge-doping effect will be largely suppressed in BN-codoped graphene. The nonlocally distributed doping holes/electrons in graphene enhance the stability of H adatom within the range of at least 9 Å away from the B/N dopants, while locally distributed holes/electrons in the vicinity of the B or N impurities only have a considerable stabilizing effect on the H adatom close (∼2 Å) to the dopants. These nonlocal and local electrochemical effects revealed here are useful for further doping-charge controlling and chemical engineering in doped graphene. Our results also clarify the issue of that the dopant-induced strain has a negligible effect on the enhanced stability of H adatom.

We present a systematic investigation of magnetic anisotropy induced by oblique deposition of Co thin films on MgO (001) substrates by molecular beam epitaxy at different deposition angles, i.e., 0 • , 30 • , 45 • , 60 • , and 75 • with respect to the surface normal. Low energy electron diffraction (LEED), surface magneto-optical Kerr effect (SMOKE), and anisotropic magnetoresistance (AMR) setups were employed to investigate the magnetic properties of cobalt films. The values of in-plane uniaxial magnetic anisotropy (UMA) constant K u and four-fold magnetocrystalline anisotropy constant K 1 were derived from magnetic torque curves on the base of AMR results. It was found that the value of K u increases with increasing deposition angle with respect to the surface normal, while the value of K 1 remains almost constant for all the samples. Furthermore, by using MOKE results, the K u values of the films deposited obliquely were also derived from the magnetization curves along hard axis. The results of AMR method were then compared with that of hard axis fitting method (coherent rotation) and found that both methods have almost identical values of UMA constant for each sample.

Taking a Sino-German Cooperation project—a demonstration project for energy-saving renovation of existing residential buildings in Changfeng Residential District of Taiyuan University of Technology—as an example, this paper introduces an energy-saving renovation scheme for this district and analyzes the results of energy efficiency inspection after renovation with an attempt to provide references for energy-saving renovation of existing residential buildings in the northern heating zone.

The experiment is to extract lignin from straw as the basic material, then to develop cheap resin. By mechanical foaming, we are to research lignin-based epoxy compounds with commercial foaming agent or sodium lauryl sulfate and the foam stabilizing effect under the experimental condition that adding or not coagulant. The study shows that the actual amount of foam can change the strength and weight of foam concrete to some extent. The results of experimental show that the lignin-based epoxy resins prepared by inexpensive straw can be applied YX-M-8-type foaming agent and the modification of sodium dodecyl sulfate in order to improve the utilization of straw, with great social and economic benefits. CLC:TU522 Document Code:A