Ji Feng

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A two-dimensional honeycomb lattice harbours a pair of inequivalent valleys in the k-space electronic structure, in the vicinities of the vertices of a hexagonal Brillouin zone, K(±). It is particularly appealing to exploit this emergent degree of freedom of charge carriers, in what is termed 'valleytronics'. The physics of valleys mimics that of spin, and(More)
An optoelectronic material with a spatially varying bandgap that is tunable is highly desirable for use in photovoltaics, photocatalysis and photodetection. Elastic strain has the potential to be used to achieve rapid and reversible tuning of the bandgap. However, as a result of plasticity or fracture, conventional materials cannot sustain a high enough(More)
This letter describes the formation of two-dimensional ͑2D͒ crystals of dipolar particles ͑TN͒ made of electrostatically charged, joined, millimeter-scale Teflon ͑T͒ and nylon-6,6 ͑N͒ spheres, and the separation of these crystals, as a distinct phase, from a mixture of TN and similar, capacitively charged particles that were coated with gold ͑Au 2 ͒. The(More)
In purely bent ZnO microwires, the excitons can be effectively driven and concentrated by the elastic strain-gradient towards the tensile outer side of the purely bent wire. Experimental and theoretical approaches are combined to investigate the dynamics of excitons in an inhomogeneous strain field with a uniform elastic strain-gradient. Cathodoluminescence(More)
Optimizing the electronic structures and carrier dynamics in semiconductors at atomic scale is an essential issue for innovative device applications. Besides the traditional chemical doping and the use of homo/heterostructures, elastic strain has been proposed as a promising possibility. Here, we report on the direct observation of the dynamics of exciton(More)
This article describes a new procedure for generating and transmitting a message--a sequence of optical pulses--by aligning a mask (an opaque sheet containing transparent "windows") below a microfluidic channel in which flows an opaque continuous fluid containing transparent droplets. The optical mask encodes the message as a unique sequence of windows that(More)
In situ observations of the nucleation and growth of atomically sharp graphene bilayer edges A B S T R A C T Using in situ transmission electron microscopy, we observed the nucleation and growth of graphene bilayer edges (BLE) with ''fractional nanotube''-like structure from the reaction of graphene monolayer edges (MLEs). Most BLEs showed atomically sharp(More)
Davisson RL. COX-1-derived PGE2 and PGE2 type 1 receptors are vital for angiotensin II-induced formation of reactive oxygen species and Ca 2ϩ influx in the subfornical organ. of blood pressure by angiotensin II (ANG II) is a process that involves the reactive oxygen species (ROS) and calcium. We have shown that ANG-II type 1 receptor (AT1R) and(More)