Synthesis of wafer-scale uniform molybdenum disulfide films with control over the layer number using a gas phase sulfur precursor

We describe a method for synthesizing large-area and uniform molybdenum disulfide films, with control over the layer number, on insulating substrates using a gas phase sulfuric precursor (H2S) and a molybdenum metal source. The metal layer thickness was varied to effectively control the number of layers (2 to 12) present in the synthesized film. The films were grown on wafer-scale Si/SiO2 or quartz substrates and displayed excellent uniformity and a high crystallinity over the entire area. Thin film transistors were prepared using these materials, and the performances of the devices were tested. The devices displayed an on/off current ratio of 10(5), a mobility of 0.12 cm(2) V (1) s (1) (mean mobility value of 0.07 cm(2) V-1 s(-1)), and reliable operation.close9

Pixel-wise distortion model and its calibration method for AMCW LiDAR

1

Nonimaging Optical Irradiance Optimization for Enhanced ROI of Mobile Robot LiDAR

1

A Novel Omnidirectional Depth Perception Method for Multi-rotor Micro Aerial Vehicles

1

A Distortion Model of Laser Sheet for a Laser Line Scanner With Large Fan Angle

This article proposes an analytical method of computing distorted laser sheet of a laser line scanner and compensating it. In this article, a distortion model of laser sheet generated from a laser line scanner with large fan angle is derived from physical principles to achieve accurate depth perception even around its edges on which significant depth estimation errors occur in existing algorithms. From a laser beam incident obliquely on a contact surface of two cylindrical lenses, a curved laser sheet is expressed in terms of the nonzero incident angle by the laws of geometrical optics. From the mathematical model of the distorted laser sheet, the incident angle is estimated through an optimization technique and then its estimate is used for depth computation. It is shown through simulations and experiments that the proposed distortion model enables a proper compensation scheme and hence the distortion-compensated depth estimation errors are reduced all over the range of interest, specially much around the both side edges of the laser sheet. Quantitatively in comparison to the compensation-free method, the depth estimation error is improved from 225 to 28 mm on average and from 1781 to 187 mm for worst-case scenarios near edges of a laser sheet.11Nsciescopu

Interference-Compensating Magnetometer Calibration With Estimated Measurement Noise Covariance for Application to Small-Sized UAVs

This article proposes a new interference-compensating magnetometer calibration scheme aided by a gyroscope sensor, which could reduce the effect of induced magnetic interference due to nearby onboard current flow. By using the innovation process and a linear matrix inequality approach, mean and variance of the induced magnetic interference are estimated to ensure that their physical meaningful values are taken to be closest to the empirically measured ones. The values are reflected in the update step of the extended Kalman filter in order to accurately estimate the calibration parameters and the corresponding direction. Results of experiments performed using a real unmanned aerial vehicle (UAV) demonstrate that the proposed calibration scheme compensates well for the disturbing magnetic interference arising from the UAV's onboard current and hence reduces the estimation error of its yaw angle, or its heading direction, by approximately two-thirds of that obtained using the existing scheme.11Nsciescopu

A Collaborative CPU Vector Offloader: Putting Idle Vector Resources to Work on Commodity Processors

Most modern processors contain a vector accelerator or internal vector units for the fast computation of large target workloads. However, accelerating applications using vector units is difficult because the underlying data parallelism should be uncovered explicitly using vector-specific instructions. Therefore, vector units are often underutilized or remain idle because of the challenges faced in vector code generation. To solve this underutilization problem of existing vector units, we propose the Vector Offloader for executing scalar programs, which considers the vector unit as a scalar operation unit. By using vector masking, an appropriate partition of the vector unit can be utilized to support scalar instructions. To efficiently utilize all execution units, including the vector unit, the Vector Offloader suggests running the target applications concurrently in both the central processing unit (CPU) and the decoupled vector units, by offloading some parts of the program to the vector unit. Furthermore, a profile-guided optimization technique is employed to determine the optimal offloading ratio for balancing the load between the CPU and the vector unit. We implemented the Vector Offloader on a RISC-V infrastructure with a Hwacha vector unit, and evaluated its performance using a Polybench benchmark set. Experimental results showed that the proposed technique achieved performance improvements up to 1.31× better than the simple, CPU-only execution on a field programmable gate array (FPGA)-level evaluation

Shifting of surface plasmon resonance due to electromagnetic coupling between graphene and Au nanoparticles

10.1364/OE.20.019690Optics Express201819690-1969