A Computational Study on the Aerodynamics of a 90 mm Ducted Contra-Rotating Lift Fan

In this paper, a steady 3D numerical study has been conducted on a 90 mm counter rotating lift fan to investigate its aerodynamic performance. The effect of axial distance between the fans and rotor speed are studied. A low thrust generation has been revealed from the simulation results due to the unfavourable working condition for the upstream...

Off-board Visual Odometry and Control of an Ultralight Quadrotor MAV

In this paper, we propose an approach to autonomously control a quadrotor micro aerial vehicle (MAV). With take-off weight of 50 g and 8-min flight endurance, the MAV platform codenamed ‘KayLion’ developed by the National University of Singapore (NUS) is able to perform autonomous flight with pre-planned path tracking. The vision-based...

Tunable Luminescence of CeAl11O18 Based Phosphors by Replacement of (AlO)+ by (SiN)+ and Co-Doping with Eu

A series of Si-N or Eu-Li doped CeAl11O18 and CeAl12O18N phosphors are prepared by solid–state reaction. Their structure and luminescence are researched carefully. Si-N doping with the concentration less than 8% can be successfully dissolved into CeAl11O18 crystal lattice and doesn't change the matrix structure, only resulting in crystal lattice...

Programmable architecture for quantum computing

A programmable architecture called “quantum FPGA (field-programmable gate array)” (QFPGA) is presented for quantum computing, which is a hybrid model combining the advantages of the qubus system and the measurement-based quantum computation. There are two kinds of buses in QFPGA, the local bus and the global bus, which generate the cluster...

The tidal wave system in the Chinese marginal seas

A 2D large-scale tidal wave model is set up for the Chinese marginal seas and it is proved to simulate the tidal motion in this large domain well. Based on the model, sensitivity analyses have been carried out to investigate the influences of various factors on the tidal wave system. According to the results, the effect of river discharges and...

The genesis of the radial tidal current off the Central Jiangsu Coast

One of the characteristics of the radial sand ridge field (RSRF) in the South Yellow Sea off the Jiangsu coast is the distinctive radial tidal current field. Although many studies have focused on the hydrodynamic environment around radial sand ridges, the knowledge on the genesis of the radial tidal current is still in a very basic stage. This...

Binding crystalline solids at low temperatures

Crystalline solids are solid materials whose constituent atoms, molecules, or ions are arranged in a highly regulated fashion. Due to lack of rotational freedom in their stacking, they have been known as fragile materials. Even though some efforts have been dedicated to bind or mend defects/cracks in amorphous materials like concrete or polymers...

Tuning the stress induced martensitic formation in titanium alloys by alloy design

Cloud droplet activation of mixed organic-sulfate particles produced by the photooxidation of isoprene

The cloud condensation nuclei (CCN) properties of ammonium sulfate particles mixed with organic material condensed during the hydroxyl-radical-initiated photooxidation of isoprene (C5H8) were investigated in the continuous-flow Harvard Environmental Chamber. CCN activation curves were measured for organic particle mass concentrations of 0.5 to...

A CMOS Image Sensor With In-Pixel Buried-Channel Source Follower and Optimized Row Selector

This paper presents a CMOS imager sensor with pinned-photodiode 4T active pixels which use in-pixel buried-channel source followers (SFs) and optimized row selectors. The test sensor has been fabricated in a 0.18-mum CMOS process. The sensor characterization was carried out successfully, and the results show that, compared with a regular imager...

Detecting changes in extreme precipitation and extreme streamflow in the Dongjiang River Basin in southern China

Detecting long-memory: Monte Carlo simulations and application to daily streamflow processes