Transfer-free synthesis of doped and patterned graphene films.

High-quality and wafer-scale graphene on insulating gate dielectrics is a prerequisite for graphene electronic applications. For such applications, graphene is typically synthesized and then transferred to a desirable substrate for subsequent device processing. Direct production of graphene on substrates without transfer is highly desirable for simplified device processing.

Phototransistor based on single In₂Se₃ nanosheets.

Micrometer-sized single-crystalline In₂Se₃ nanosheets are synthesized by epitaxial growth from In₂Se₃nanowires. The In₂Se₃ nanosheets possess anisotropic structural configuration with intralayer covalent bonding and interlayer van der Waals bonding. Phototransistors based on the In₂Se₃ nanosheets are realized, and the devices show high photoresponsivity and high photo On/Off ratio up to two orders.

Intrinsic Ge nanowire nonvolatile memory based on a simple core-shell structure.

Intrinsic Ge nanowires (NWs) with a Ge core covered by a thick Ge oxide shell are utilized to achieve nanoscale field-effect transistor nonvolatile memories, which show a large memory window and a high ON/OFF ratio with good retention. The retainable surface charge trapping is considered to be responsible for the memory effect, and the Ge oxide shell plays a key role as the insulating tunneling dielectric which must be thick enough to prevent stored surface charges from leaking out. Annealing the device in air is demonstrated to be a simple and effective way to attain thick Ge oxide on the Ge NW surface, and the Ge-NW-based memory corresponding to thick Ge oxide exhibits a much better retention capability compared with the case of thin Ge oxide.

Treatment of thoracolumbar fracture with pedicle screws at injury level: a biomechanical study based on three-dimensional finite element analysis.

The aim of this study was to investigate the biomechanical mechanisms of treatment of thoracolumbar compression fracture with pedicle screws at injury level based on a three-dimensional finite element method. We constructed one three-dimensional finite element model of T11-L1 in a patient with a compression fracture of the T12 vertebral body(anterior edges of vertebral body were compressed to 1/2, and kyphosis Cobb angle was 18.6°) fixed by four pedicle screws and another model fixed by six pedicle screws at the injured vertebrae, and then assigned different forces to the two models to account for axial compression, flexion, extension, left lateral bending, and rightward axial rotation by Ansys software.

[A biomechanical study on cervical spinal posture and prior loading history affecting spinal compressive strength].

Objective: The purpose of this study is to investigate the effect of cervical spinal posture and prior loading history on spinal compressive strength.

Methods: Twelve human cadaver cervical spines were harvested and dissected into 24 motion segments containing 2 vertebrae and the intervertebral discs (C3,4 and C5,6). Compressive loads were applied on so that the effects of 2 loading conditions (dehydrated, superhydrated) and 2 postures (neutral trunk, flexed) could be examined.