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The existence of nontrivial Berry phases associated with two inequivalent valleys in graphene provides interesting opportunities for investigating the valley-projected topological states. Examples of such studies include observation of anomalous quantum Hall effect in monolayer graphene, demonstration of topological zero modes in molecular graphene assembled by scanning tunneling microscopy, and detection of topological valley transport either in graphene superlattices or at bilayer graphene domain walls. However, all aforementioned experiments involved non-scalable approaches of either mechanically exfoliated flakes or atom-by-atom constructions. Here we report an approach to manipulating the topological states in monolayer graphene via nanoscale strain engineering at room temperature. By placing strain-free monolayer graphene on architected nanostructures to induce global inversion symmetry breaking, we demonstrate the development of giant pseudo-magnetic fields (up to 800 Tesla), valley polarization, and periodic one-dimensional topological channels for protected propagation of chiral modes in strained graphene, thus paving a pathway towards scalable graphene-based valleytronics., Comment: Manuscript (5 Figures, 14 pages) and Supplementary Material (9 Figures, 11 pages), published in Science Advances

Structural distortions in nano-materials can induce dramatic changes in their electronic properties. This situation is well manifested in graphene, a two-dimensional honeycomb structure of carbon atoms with only one atomic layer thickness. In particular, strained graphene can result in both charging effects and pseudo-magnetic fields, so that controlled strain on a perfect graphene lattice can be tailored to yield desirable electronic properties. Here we describe the theoretical foundation for strain-engineering of the electronic properties of graphene, and then provide experimental evidences for strain-induced pseudo-magnetic fields and charging effects in monolayer graphene. We further demonstrate the feasibility of nanoscale strain engineering for graphene-based devices by means of theoretical simulations and nano-fabrication technology., Comment: 13 pages, 13 figures. Accepted for publication in Acta Mechanica Sinica (2015)

Systematic magnetic measurements have been performed in unique$\alpha - MnO_2$ square nanotubes synthesized by a facile hydrothermal method with microwave-assisted procedures. Unusual magnetic phenomena (abnormal magnetization verse temperature (M - T) behaviour, large and abnormal magnetization hysteresis loop horizontal shift (HHS) verse cooling field (HFC) behaviours (HHS - HFC) has been observed in these square nanotubes. These suggest the observation of large unfrozen orbital moment which also is the micro -original of observed large and abnormal horizontal shift (HHS). The findings demonstrated that engineering layered structures in nanoscale would create many unique nanostructures and unusual physicochemical behaviours., Comment: 23 Pgs, 10 Figs

A series of MnO2 unique nanostructures were synthesized by a facile hydrothermal method with microwave-assisted procedures. A novel nanostructure formation mechanism has been proposed, that MnO6 octahedral nuclei and molecular layers can be rearranged into different nanostructured morphologies by restacking and splitting, and then clasping, which is associated with tunnel structure phase transformation. Systematic macrostructure observations and magnetic property measurements have been conducted on these nanostructures, which demonstrate that engineering layered structures has the potential to create many unique nanostructures and unusual physicochemical behaviours., Comment: 15 Pgs, 7 Figs

This paper presents synthesis methods and multifunctional properties of porous Co3O4 nanoplatelets and nanowires. Surprisingly, significantly superior Li-ion battery performance compared to other cathode materials is exhibited in the same samples as room temperature ferromagnetism (RTFM). Microstructure observations, and properties measurements and analysis indicate that the as-prepared Co3O4 nanostructures exhibit a spontaneous transformation of their morphology, showing a predominantly {110} plane orientation and preferentially presenting the Co3+ species at the surface at appreciate preparation condition. More Co3+ in an octahedral (O) position exposed on the surface is associated with more Co3+ being Co3+|\cdot (Co3+ with trapped charge carriers) or reduced to Co2+ in the O position due to surface defects or oxygen vacancies, which is possibly the mechanism of excellent electric transport properties then high Li-battery performance; at the same time, reduced to Co2+ or free charge carriers trapped by Co3+|\cdot in the O position are the role of charge carries- mediate ferromagnetism, may be the origin of RTFM as well. These results further show the importance of modifying the nanostructure of surfaces in the preparation of transition metal oxides as multidisciplinary functional materials., Comment: 34 pages, 25 figures. arXiv admin note: text overlap with arXiv:0903.5214 by other authors

A comparative study on as cast and annealed rare earth bulk metallic glass (BMG) with composition Tb36Sm20Al24Co20 has been carried out by magnetization measurements. The as cast amorphous sample shows non-ergodic magnetization but does not show the behavior expected from magnetic glass. After annealing, the partially crystallized BMG shows this magnetic glass behavior. This is confirmed by the established measurement protocol of cooling and heating in unequal fields (CHUF)., Comment: Presented at 56th DAE-Solid State Physics Symposium (DAE-SSPS), Dec-2011, Chennai, India

By microalloying of Gd atoms with 4f electrons into CuZrAl or MgCuY glassy alloys, they display a variety of puzzling behaviors such as the characteristic of Kondo effect. The ground states of the Gd-alloyed systems are determined to have non-Fermi-liquid characteristics which derive from the strong structural disorder. The Kondo effect in these glassy alloys is attributed to the strong structural disorder. The coexistence of the Kondo effect and strong structural disorder has implications for the understanding the origin of the puzzling non-Fermi-liquid behavior., Comment: 12 page, 4 figures

We report that both shear and bulk moduli, not only shear modulus, are critical parameters involved in both homogeneous and inhomogeneous flows in metallic glass. The flow activation energy (\Delta F) of various glasses when scaled with average molar volume Vm, which is defined as flow activation energy density \rho_E =\Delta F/Vm, can be expressed as: D=(10G+K)/11 . The extended elastic model is suggestive for understanding the glass transition and deformation in metallic glasses., Comment: 14 pages, 3 figures, 1 table

The Beijing Electron-Positron Collider (BEPC) has been running for both high energy physics (HEP) and synchrotron radiation (SR) researches since 1989. Good performance of BEPC accomplishes a lot of achievements in the tau-charm region over the past decade, and in many fields of SR applications as well. As an upgrading scheme from BEPC, the BEPCII project was approved by the Chinese government in the early time of this year, with a micro-beta scheme and multi-bunch collision in a doublering machine installed in the current BEPC tunnel. The design work of the BEPCII is being carried on. This paper will describe the main progresses on the design of the BEPCII in the field of accelerator physics., Comment: Invited talk at the Workshop on e+e- in the 1-2 GeV range, Alghero, Italy, September 2003 (eConf C0309101)